mysql> explain select id from amenities where id=2;
+----+-------------+-----------+-------+---------------+---------+---------+-------+------+-------------+
| id | select_type | table     | type  | possible_keys | key     | key_len | ref   | rows | Extra       |
+----+-------------+-----------+-------+---------------+---------+---------+-------+------+-------------+
|  1 | SIMPLE      | amenities | const | PRIMARY       | PRIMARY | 4       | const |    1 | Using index |
+----+-------------+-----------+-------+---------------+---------+---------+-------+------+-------------+
1 row in set (0.00 sec)