There won't be a Steam key if you bought it on itch.io - there are links to download the binaries of the game in your library. If you want a Steam key, you need to buy a Steam key!

If you bought the game individually, you can get the Steam Key from the downloads page, BUT if you got it as a part of one of the giant bundles, there's no Steam Key included with those.

I bought it as a standalone thing. still no key