Depending on the plate you purchase the screws will be shallow enough that they won't even hit the wall. If they do contact the wall, but only a little bit, do nothing. If they hit the wall a lot it will push the plate off the wall, in this case use something to knock away a small amount of the sheetrock to create a small recess for the screw to sit in. This is the correct way for an outlet to be installed, against the sheetrock like that. It is all fire rated.