mysql> use smartorrent
Database changed
mysql> EXPLAIN SELECT * FROM bts_users WHERE last_seen > 1175967022 - 900 ORDER BY last_seen DESC;
+----+-------------+-----------+------+---------------+------+---------+------+--------+-----------------------------+
| id | select_type | table     | type | possible_keys | key  | key_len | ref  | rows   | Extra                       |
+----+-------------+-----------+------+---------------+------+---------+------+--------+-----------------------------+
|  1 | SIMPLE      | bts_users | ALL  | last_seen     | NULL |    NULL | NULL | 379021 | Using where; Using filesort |
+----+-------------+-----------+------+---------------+------+---------+------+--------+-----------------------------+
1 row in set (0.20 sec)

mysql>