+----+-------------+----------+-------+---------------+--------+---------+------+-----------+--------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+----------+-------+---------------+--------+---------+------+-----------+--------------------------+ | 1 | SIMPLE | activity | index | parent | parent | 9 | NULL | 113020037 | Using where; Using index | +----+-------------+----------+-------+---------------+--------+---------+------+-----------+--------------------------+ 1 row in set (0.48 sec) +----+-------------+----------+-------+---------------+--------+---------+------+------+--------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+----------+-------+---------------+--------+---------+------+------+--------------------------+ | 1 | SIMPLE | activity | range | parent | parent | 9 | NULL | 7933 | Using where; Using index | +----+-------------+----------+-------+---------------+--------+---------+------+------+--------------------------+ 1 row in set (0.56 sec)