Unique Password Protection

So, I’m in the midst of talking with my employer and he wants a plugin that I haven’t been able to track down. either because it doesn’t exist or because I used the wrong search terms.

What we need is a plugin that generates keys like product keys or serial numbers, that it uses for its login on the site. The keys should also have a limited activation lifespan as we’re selling them for an online escape game.

I’ve already looked into several password protection plugins like the plugin Password Protected, but it only sets up a normal password. We’ve also thought about changing the password every day, but that just adds to our workload and we want it automized.

Another thing we tried looking into was an Authenticator style login where we generate a bunch of keys and that key could only be used once, but that wouldn’t solve our problems

Is it feasible or are we on a wild goose chase here?