It is small enough not to even bother with a collider for the sake of collision, but we do need to be able to pick it.
That’s the other reason to use a collider: to be pickable with the cursor, an object must have a collider.
You are probably zoomed-in quite close at this point. If you zoom out a bit, you’ll realize that the key mesh presents
a pretty small target for a mouse pick. It would make much more sense to exchange its Mesh Collider for a Box Collider.