Help with explain query and code 1003

[Aaron Zeckoski]

I have the following query which is showing up as a slow query (it appears to get slower the more items I have in the system):

mysql> explain extended SELECT COUNT(*) FROM wp_term_relationships, wp_posts WHERE wp_posts.ID = wp_term_relationships.object_id AND post_status = 'publish' AND post_type = 'post' AND term_taxonomy_id = 1;
+----+-------------+-----------------------+--------+--------------------------------------+------------------+---------+--------------------------------------+------+----------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+-------------+-----------------------+--------+--------------------------------------+------------------+---------+--------------------------------------+------+----------+-------------+
| 1 | SIMPLE | wp_term_relationships | ref | PRIMARY,term_taxonomy_id | term_taxonomy_id | 8 | const | 9190 | 100.00 | Using index |
| 1 | SIMPLE | wp_posts | eq_ref | PRIMARY,type_status_date,post_status | PRIMARY | 8 | dcwp.wp_term_relationships.object_id | 1 | 100.00 | Using where |
+----+-------------+-----------------------+--------+--------------------------------------+------------------+---------+--------------------------------------+------+----------+-------------+
2 rows in set, 1 warning (0.00 sec)

mysql> show warnings;
+-------+------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Level | Code | Message |
+-------+------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Note | 1003 | select count(0) AS `COUNT(*)` from `dcwp`.`wp_term_relationships` join `dcwp`.`wp_posts` where ((`dcwp`.`wp_term_relationships`.`term_taxonomy_id` = 1) and (`dcwp`.`wp_posts`.`ID` = `dcwp`.`wp_term_relationships`.`object_id`) and (`dcwp`.`wp_posts`.`post_status` = 'publish') and (`dcwp`.`wp_posts`.`post_type` = 'post')) |
+-------+------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

Here is the output from running the query:

mysql> SELECT COUNT(*) FROM wp_term_relationships, wp_posts WHERE wp_posts.ID = wp_term_relationships.object_id AND post_status = 'publish' AND post_type = 'post' AND term_taxonomy_id = 1;
+----------+
| COUNT(*) |
+----------+
| 18000 |
+----------+
1 row in set (0.11 sec)

I don't understand what the 1003 means or what I should do to try to speed this up. Does anyone have any suggestions?
Thanks