Slow queries. need adivce on creating indexes

[Orbiz Gam]

Hi,

I have a gaming portal that is powered by PHP+MySql.
the queries take too long (some take about half a second).
I think it's a problem with the indexes of the tables.

bellow is the datbase starcture including it's indexes and number of rows, followed by the quries I run (there are just a couple)

The database structure:
-- phpMyAdmin SQL Dump
-- version 3.4.10.1
-- Server version: 5.5.41
-- PHP Version: 5.2.2

SET SQL_MODE="NO_AUTO_VALUE_ON_ZERO";
SET time_zone = "+00:00";

/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
/*!40101 SET NAMES utf8 */;

--
-- Table structure for table `categories`
--

CREATE TABLE IF NOT EXISTS `categories` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(255) COLLATE utf8_unicode_ci NOT NULL DEFAULT '',
`active` varchar(3) COLLATE utf8_unicode_ci NOT NULL DEFAULT '',
`order` char(3) COLLATE utf8_unicode_ci NOT NULL DEFAULT '0',
`parent` varchar(3) COLLATE utf8_unicode_ci NOT NULL DEFAULT 'yes',
`home` varchar(3) COLLATE utf8_unicode_ci NOT NULL DEFAULT 'yes',
`desc` varchar(255) COLLATE utf8_unicode_ci NOT NULL DEFAULT '',
`pid` varchar(3) COLLATE utf8_unicode_ci NOT NULL DEFAULT '',
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=25 ;

/*
Indexes:
Keyname Type Unique Packed Column Cardinality Collation Null Comment
PRIMARY BTREE Yes No id 21 A

Row Statistics:
Format dynamic
Collation utf8_unicode_ci
Rows 21
*/

-- --------------------------------------------------------

--
-- Table structure for table `featuredgames`
--

CREATE TABLE IF NOT EXISTS `featuredgames` (
`gameid` int(11) unsigned NOT NULL,
`add_date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`gameid`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

/*
Indexes:
Keyname Type Unique Packed Column Cardinality Collation Null Comment
PRIMARY BTREE Yes No gameid 23 A

Space usage Type Usage
Data 207 B
Index 2,048 B
Total 2,255 B

Row Statistics:
Format static
Collation utf8_general_ci
Rows 23
*/
-- --------------------------------------------------------

--
-- Table structure for table `games`
-- (this is the big one with over 20,000 records)

CREATE TABLE IF NOT EXISTS `games` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`title` text COLLATE utf8_unicode_ci NOT NULL,
`description` text COLLATE utf8_unicode_ci NOT NULL,
`instructions` text COLLATE utf8_unicode_ci NOT NULL,
`keywords` text COLLATE utf8_unicode_ci NOT NULL,
`file` text COLLATE utf8_unicode_ci NOT NULL,
`height` int(11) NOT NULL DEFAULT '0',
`width` int(11) NOT NULL DEFAULT '0',
`category` int(11) NOT NULL DEFAULT '0',
`plays` int(11) NOT NULL DEFAULT '0',
`code` text COLLATE utf8_unicode_ci NOT NULL,
`type` enum('IMAGE','MOV','MPG','AVI','FLV','WMV','SWF','DCR','UNITY','YOUTUBE','CustomCode') COLLATE utf8_unicode_ci NOT NULL DEFAULT 'SWF',
`source` enum('OTHER','FGD','FOG','KONGREGATE','AGF','MGF') COLLATE utf8_unicode_ci NOT NULL DEFAULT 'OTHER',
`sourceid` int(11) unsigned NOT NULL,
`thumbnail` text COLLATE utf8_unicode_ci NOT NULL,
`ismochi` int(10) NOT NULL DEFAULT '0',
`thumbnail_200` varchar(255) CHARACTER SET utf8 NOT NULL,
`screen1` varchar(255) CHARACTER SET utf8 NOT NULL,
`screen2` varchar(255) CHARACTER SET utf8 NOT NULL,
`screen3` varchar(255) CHARACTER SET utf8 NOT NULL,
`screen4` varchar(255) CHARACTER SET utf8 NOT NULL,
`review` text CHARACTER SET utf8 NOT NULL,
`active` tinyint(4) NOT NULL DEFAULT '1',
PRIMARY KEY (`id`),
KEY `source` (`source`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=29576 ;

/*
Indexes:
Keyname Type Unique Packed Column Cardinality Collation Null Comment
PRIMARY BTREE Yes No id 25965 A
source BTREE No No source 4 A

Space usage Type Usage
Data 8,618.9 KiB
Index 567.0 KiB
Total 9,185.9 KiB

Row Statistics:
Format dynamic
Collation utf8_unicode_ci
Rows 25,965
*/
-- --------------------------------------------------------

--
-- Table structure for table `ratingsbar`
--

CREATE TABLE IF NOT EXISTS `ratingsbar` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`total_votes` int(11) NOT NULL DEFAULT '0',
`total_value` int(11) NOT NULL DEFAULT '0',
`used_ips` longtext,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=29576 ;

/*
Indexes:
Keyname Type Unique Packed Column Cardinality Collation Null Comment
PRIMARY BTREE Yes No id 1797 A

Space usage Type Usage
Data 42,440 B
Index 23,552 B
Total 65,992 B

Row Statistics:
Format dynamic
Collation latin1_swedish_ci
Rows 1,797
*/
-- --------------------------------------------------------


/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
/*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
/*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;


---------------------------------------------------------
END database stracture.

Now these are the main queries I'm using (to my understanding, this information is important when it comes to indexes):
I don't use any UPDATE or INSERT queries for these tables, I just use SELECT queries:
------------
query to get featured games:
"SELECT `id` , `title` , `thumbnail` , `description` , `plays`
FROM `games`
INNER JOIN `featuredgames` ON `games`.`id` = `featuredgames`.`gameid`
where active='1'
ORDER BY rand()
LIMIT 50 "

query to get random games (slow query... takes half a second to run):
"SELECT games.id, games.title, games.thumbnail, games.description, games.plays, categories.name
FROM games
INNER JOIN categories ON games.category=categories.id
WHERE games.active='1'
AND categories.id NOT IN (8,19,12,24)
ORDER BY rand()
LIMIT 20"

get top rated games ordered by ratings:
"SELECT `games`.`id`, `title`, `thumbnail`, `description`, `plays`
FROM `games` INNER JOIN `ratingsbar` ON `games`.`id` = `ratingsbar`.`id`
where active='1' AND `ratingsbar`.`total_votes` > 0
ORDER BY `ratingsbar`.`total_value`/`ratingsbar`.`total_votes` DESC, `ratingsbar`.`total_votes` DESC LIMIT 90"

get most played games :
"SELECT `games`.`id`, `title`, `thumbnail`, `description`, `plays`
FROM `games` where active='1' order by plays DESC LIMIT 10"

get games in certain category ordered by ratings (this one takes too long, about half a second):
"SELECT `games`.`id`, `games`.`title`, `games`.`thumbnail`, `games`.`description`, `games`.`plays` , `ratingsbar`.`total_value`/`ratingsbar`.`total_votes` as ratings
FROM `games` LEFT JOIN `ratingsbar` ON `games`.`id` = `ratingsbar`.`id`
where active='1' AND category = " . $id . "
ORDER BY `ratingsbar`.`total_value`/`ratingsbar`.`total_votes` DESC, `ratingsbar`.`total_votes` DESC LIMIT 90"

get deatils of certain game: "SELECT * FROM `games` where active='1' and id = ".$id
----------

that's it.
are my indexes ok ? should I add more ?