Due to a higher-than-expected demand we're temporarily out of keys for To The Moon, and working to get more. Unfortunately we cannot guarantee these will arrive to us before the indie weekend promotion is over, but will do everything we can.
It's especially unfortunate because To The Moon is an incredible experience, and even if you can't get it now, you should definitely make sure to pick it up at some point.
Update 2303 GMT March 16th: We now have more stock of this :) Thanks to Kan Gao for being very quick to react! If you get it now, make sure to thank him!