There is no requirement that the receptacle be on the wall at all.... in a box, sitting atop the floor, is perfectly OK. And, since the receptacle is "atop" and not "in" the floor, it need not be a floor receptacle.
Now, I'm not saying that this arrangement makes me happy. Truth be known, there are very few stove installations that I am happy with. The situation is not made any better by the lack of space behind the stove! (After all, folks want the stove against the wall- not pushed out 3").
Two things to take care of: The cord and the box.
The box needs to be anchored, and not sliding around.
The wire supplying the box needs support and protection. If the wire is Romex, this means a proper fitting where it enters the box.
