SELECT COUNT(*) FROM (select distinct id, procname, operation, path, user, datetime from lastlogs
where user = 'UNITED-TSERVER1\\Serveradmin' and datetime > '2009-5-12 08:00' and datetime < '2009-5-12 09:00') AS count_table;

+----------+
| COUNT(*) |
+----------+
|  1064997 |
+----------+
1 row in set (18 min 30.23 sec)

Az explain:

+----+-------------+----------+-------+---------------+------+---------+------+---------+------------------------------+
| id | select_type | table    | type  | possible_keys | key  | key_len | ref  | rows    | Extra                        |
+----+-------------+----------+-------+---------------+------+---------+------+---------+------------------------------+
|  1 | PRIMARY     | NULL     | NULL  | NULL          | NULL | NULL    | NULL |    NULL | Select tables optimized away |
|  2 | DERIVED     | lastlogs | range | user          | user | 776     | NULL | 1223112 | Using where                  |
+----+-------------+----------+-------+---------------+------+---------+------+---------+------------------------------+
2 rows in set (18 min 6.36 sec)