In case the OP is NOT flying EK (although if not, this is the wrong forum )

In T1 it is very unlikely you'd find plugs. In T3, perhaps more possible. They usually have them for vacuum cleaners or floor polishers

That said, I wouldn't have said there is anywhere at all comfortable to spend an overnight landside at DXB. There's a cafe in arrivals in T1 but not sure if it'd be open all night; very few seats otherwise.