You have to pay a premium for the night shifts, so no grocery store will support that (unless the owners work themselves or their families for submarket rates).
The premium for night shifts isn't what it once was, anymore. The fact that most groceries close 22:00 sharp just shows how insanely low their revenue is. Few exceptions exists in places where it makes sense volume-wise. 'Spätis' exist mostly in Berlin https://en.wikipedia.org/wiki/Sp%C3%A4tkauf
I know of a few others in my town, where they are simply called 'Kiosk'.