How do i disable my keyboard in favor of my wireless keyboard?

My problem is that some time ago, my nephew got a hold of my macbook and pounded on the keys to the point were half of them don't work. I got a wireless keyboard, but often the screeen starts scrolling by itself as what i would imagine the arrow keys get stuck on. in other words, sometimes certain keys on the built in keyboard randomly go off, because of the damage, which seriously hinders anything else i try to do. I'd like to turn off the keys on the computer itself, and only use the wireless for input but i haven't been able to find an option in the system settings. I'm not sure if this is the best idea...as i can imagine a situation where my wireless breaks and i can't enter the password to access the computer or pair a new device. I'd imagine I'd have to have access to pair a new wireless keyboard, as i assume their not all addressed the same. (i'd think that would be a problem in say, an office full of them). Maybe the solution is to have the OG keys repaired, but i don't know if its doable, or what that costs...any help would be appreciated. thanks.