How do i get my steam key for FTW i purchased long ago with the promise of a steam key in return for the support on itch.io?

Hi, yes you can request a steam key in itch.io
Here is a link with instructions: https://itch.io/t/67604/how-to-get-a-steam-key-from-your-itchio-purchase

Did this end up working?

I followed the steps Massive Galaxy Studios recommended, arrived at the download page, and didn't see the "Claim Steam Key" section or button.