Having a 'key code' associated with a account to view a certain page

I am currently working on a eCommerce site that is running the latest version of wordpress and the woocommerce plugin.

what I am trying to accomplish is when someone registers to my site they have a option to fill out a text widget called ‘Beta Key’. What i’m wanting this to do is refer back to my database of stored keys and if they match up it will allow the user to view the page, if not it will throw a 403 page.

To summarize:

If user does not have validated beta key:

1. User will click on shop, it will redirect to maybe a page to enter the key.

If user has validated beta key:

1. User registers, enters beta key along with usual ‘username’ ‘password’ credentials

2. When user clicks on shop, it will reference to my keys in the database and allow user to view products