The story
* (praiseworthy and admirable): Coined by Soyjak.party users upset at the widened usage of based (“praiseworthy and admirable, particularly in a perceived countercultural sense”) outside of their community. Most likely simply from the verb key; in slang perhaps connected to the "securing" action of a lock and key (compare e.g. scored).
Etymology from Wiktionary, CC BY-SA 4.0.