Problem with result field list

[Adrian Chapela Cordeiro]

Hello,

I have the next query:
SELECT gis_id, lat, long FROM gis WHERE lat > '40.4660506896973' AND lat < '40.4675506896973' AND long > '-3.65449994277954' AND long < '-3.65299994277954' LIMIT 10000;

and this other:
SELECT gis_id, lat, long, z1,z2,z3 FROM gis WHERE lat > '40.4660506896973' AND lat < '40.4675506896973' AND long > '-3.65449994277954' AND long < '-3.65299994277954' LIMIT 10000;

The table is:
+----------+---------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------+---------------------+------+-----+---------+----------------+
| gis_id | bigint(20) unsigned | | PRI | NULL | auto_increment |
| lat | double | | MUL | 0 | |
| long | double | | | 0 | |
| z1 | varchar(22) | | | | |
| z2 | varchar(50) | | | | |
| z3 | varchar(100) | | | | |
+----------+---------------------+------+-----+---------+----------------+

Indexes:
+---------+------------+------------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment |
+---------+------------+------------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+
| gis | 0 | PRIMARY | 1 | gis_id | A | 4562147 | NULL | NULL | | BTREE | |
| gis | 0 | latitud__longitud__IDX | 1 | lat | A | 4562147 | NULL | NULL | | BTREE | |
| gis | 0 | latitud__longitud__IDX | 2 | long | A | 4562147 | NULL | NULL | | BTREE | |
+---------+------------+------------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+

The first query is faster than second. The second takes a lot of time, 16 seconds aprox.