I added the keys a few days ago, and I've confirmed that some of them have been received, but I'm not certain they're showing up for everyone as I expected they would.
I suspect keys may not be accessible for pay-what-you-want purchases that were below the current minimum price. That wasn't my intent, and unfortunately, I think these will have to be handled on a case-by-case basis.
If you could please send me an email (jpittman at gmail dot com) from the address associated with your itch.io account, I'll mail you back a key.