I recently came across this product:, which is a stainless steel shield to place between your mountain cleats and your carbon soled shoes, to prevent damage to the carbon.
Has anyone seen something similar for a road shoe?
You could use a pair of these stickers.
As far as I know most road cleats are plastic cleats and are not going to do significant damage to the shoe (being plastic and large rather than metal and small) so no protection is needed.
(There are some road cleats which are metal, as described in comments.)
If you're really that concerned, get a roll of 3M "copter tape" and cut it to the same size as the cleat. Given the cleat should never move, the most you should get is a bit of marking where the cleat sits which you'll never see as the cleat should never move (and it's helpful when you're replacing cleats)