lunar revel tokens: orbs or hextech keys
100 tokens = 1 orb or 10 key fragments 10 key fragments or 3 and 1/3 keys hextech chests contain a skin shard about 50% of the time, so that's more than 1.5 skin shards per 100 tokens
Revel orb contains a skin shard, an 8% chance of an additional shard, and a 4% chance of a bag with 5 shards, 1.0 + 0.08 + 0.04 * 5 = 1.28 skin shards per 100 tokens.
It looks like hextech keys are objectively a better choice to spend tokens on than orbs, kindof a shame that the special limited time boxes have such garbage contents for the price. Maybe some day Riot will learn that limited time events should have content worth engaging with.