I have added my html5 game, made in unity. I have set the status to "restricted". Then i have generated access key.  Sent it to a person, without an account on itch.io, and they saw a page with "Nothing to download yet". 

Is there something that needs to be done? Do I have to wait a couple of days for the game to finish processing?

I have edited the page to be accessible with password, and it works, but I need to have more control over it, so the keys would be ideal. 

Please help!

Well, do you have something to download yet? Download keys by definition take you straight to the download page. (There should be a link back to the game page though). For an HTML5 game, it may be better to set a password instead, or set the project page to draft and share the secret URL.

HI! 

Yes, i have the  game uploaded :) I, as a creator can play it without any problems. 

I did set the password, and it worked(like I said in the OP). But I would want to have better control over who gets the access. I want to know that the person that received the key did look at the game :)

Is this game played in the browser? If so then the key owner will have to navigate back to the project's page after attaching the key to their account to access the game. This is a issue with our UI that needs to be fixed to make it more clear.