May 2018 humble monthly gift link, popup says its not valid for CN(China).
However, according to: https://www.steamgifts.com/discussion/tOaQv/humble-bundle-may-2018-monthly-bundle-20apr-unlocks-moon-hunters-jalopy-crazy-machines-3/search?page=7#MMaHhvk this key isn't actually locked from China, so I will leave this open~

Also this game is no longer available for purchase on Steam, so its actually somewhat of a rarity~