Missing index for status on blocks

mysql> explain SELECT DISTINCT b.* FROM blocks b LEFT JOIN blocks_roles r ON b.module = r.module AND b.delta = r.delta WHERE b.status = 1 AND b.custom != 0 AND (r.rid IN (2,3,4,5,8) OR r.rid IS NULL) ORDER BY b.weight, b.module;
+----+-------------+-------+------+---------------+---------+---------+----------------------------------+------+----------------------------------------------+
| id | select_type | table | type | possible_keys | key     | key_len | ref                              | rows | Extra                                        |
+----+-------------+-------+------+---------------+---------+---------+----------------------------------+------+----------------------------------------------+
|  1 | SIMPLE      | b     | ALL  | NULL          | NULL    | NULL    | NULL                             |   61 | Using where; Using temporary; Using filesort | 
|  1 | SIMPLE      | r     | ref  | PRIMARY       | PRIMARY | 292     | drupal6.b.module,drupal6.b.delta |    1 | Using where; Using index; Distinct           | 
+----+-------------+-------+------+---------------+---------+---------+----------------------------------+------+----------------------------------------------+


alter table blocks add key status (status);

explain SELECT DISTINCT b.* FROM blocks b LEFT JOIN blocks_roles r ON b.module = r.module AND b.delta = r.delta WHERE b.status = 1 AND b.custom != 0 AND (r.rid IN (2,3,4,5,8) OR r.rid IS NULL) ORDER BY b.weight, b.module;
+----+-------------+-------+------+---------------+---------+---------+----------------------------------+------+----------------------------------------------+
| id | select_type | table | type | possible_keys | key     | key_len | ref                              | rows | Extra                                        |
+----+-------------+-------+------+---------------+---------+---------+----------------------------------+------+----------------------------------------------+
|  1 | SIMPLE      | b     | ref  | status,custom | status  | 1       | const                            |   30 | Using where; Using temporary; Using filesort | 
|  1 | SIMPLE      | r     | ref  | PRIMARY       | PRIMARY | 292     | drupal6.b.module,drupal6.b.delta |    1 | Using where; Using index; Distinct           | 
+----+-------------+-------+------+---------------+---------+---------+----------------------------------+------+----------------------------------------------+