Offhand, I say the Shepherd's Mate. But let us just consider "serious" tournament play. Still, the game must be rather short to be repeated extremely often. Could be a "Will they ever learn" opening trap or a prearranged draw line. Anyone care to research it in a megabase?
Note that just because Lichess lists 187×10^6 e4 vs. 100×10^6 d4 doesn't mean that an e4 game will be the winner! Playing always the most often played move on the analysis board I landed in the Lasker Pelikan Sveshnikov.)