I think the point of an NFT would be that everybody else can also see that you control the token, which doesn't really seem relevant to starting a car. You could just ("just") have a privately controlled public/private key pair, and the previous owner could tell the car that your public key should now be the only one able to open the car; no need to announce that to the world.

(I also know nothing of the space, just engaging to build my own understanding.)