It was clearly stated several times that we'd be getting new keys, so we were free to give away our beta keys if we didn't want to play it.
Quoting update #54 when the beta phase started:
Note, though, that when the full version of the game is released, you'll receive a NEW key to unlock your copy of the game through either Steam or GOG. Your old alpha key will then be nullified.
I hope this situation will be sorted out soon, as I gave one of my beta access key away but I still want to redeem it as a (new) Steam key
