Optimering af distinct

Jeg har et problem med en langsom sql-string eller også er det min server.. :P

Den her tager mellem 30-90 sek at køre, hver gang jeg skifter self_id (self_id = 2)

SELECT DISTINCT im.year FROM idb_movie im
  INNER JOIN idb_userself iu ON iu.idb_id = im.id AND iu.self_id = 2
  WHERE iu.self_id = 2 ORDER BY im.year DESC;


CREATE TABLE `idb_movie` (
  `id` int(11) unsigned NOT NULL auto_increment,
  `ord` tinyint(3) unsigned NOT NULL default '0',
  `title` varchar(200) NOT NULL,
  `year` smallint(1) unsigned NOT NULL default '0',
  `url` varchar(255) default '0',
  PRIMARY KEY  (`id`),
  KEY `Year` (`year`),
  FULLTEXT KEY `Title` (`title`)
) ENGINE=MyISAM AUTO_INCREMENT=212396 DEFAULT CHARSET=latin1 ROW_FORMAT=FIXED;

CREATE TABLE `idb_userself` (
  `id` int(11) unsigned NOT NULL auto_increment,
  `idb_id` int(11) unsigned NOT NULL default '0',
  `genre_id` int(11) unsigned NOT NULL default '0',
  `group_id` int(11) unsigned NOT NULL default '0',
  `self_id` int(11) unsigned NOT NULL default '0',
  `movie_number` int(11) unsigned default '0',
  PRIMARY KEY  (`id`),
  KEY `Idb` (`idb_id`),
  KEY `Genre` (`genre_id`),
  KEY `Group` (`group_id`),
  KEY `Self` (`self_id`)
) ENGINE=MyISAM AUTO_INCREMENT=20001 DEFAULT CHARSET=latin1;


Nogle forslag til hvordan jeg kan optimer den ??