People who though they can do better did JWT, that is not complicated at all and has no bugs as well. Also solves 20% of what asn.1 is used for.
replyMaybe a bit pedantic, but it would actually be the more general JOSE which includes tokens (JWT), signatures (JWS), and key transmission (JWK).
replyAnd there is a related binary format that uses CBOR (COSE) as well.