Yep, it's happened to a lot of us, see all the comments below about:
"There are no keys available at this time, try again later"
Some people have waited a few days already. The Devs are very very slow to respond about this issue.
Seems the steam keys have run out of stock on itch.io. I'll try address this issue with them when they are online. Sorry about this.
Steam keys are now available, check now!
Well it's good they are re-stocked again.
