I think you are wanting to use some % operators eg these will match anything in your like statement.
Match any tag that has the word feature in it, other letters might be on left and right of word.
$query = "select * FROM $table WHERE (tags LIKE '%feature%') ORDER BY rid DESC LIMIT 1";
Match any tag that has that start with feature and may have other words or letters after
$query = "select * FROM $table WHERE (tags LIKE 'feature%') ORDER BY rid DESC LIMIT 1";