The token is named Clue Token and has the artifact subtype Clue. Clue isn't a creature type.

The tokens are normal artifacts. For example, one can be sacrificed to activate the ability of Breya's Apprentice and one can be the target of Break Ties.

You can't sacrifice a Clue to activate its own ability and also to activate another ability that requires sacrificing a Clue (or any artifact) as a cost, such as that of Lonis, Cryptozoologist.