UPDATE a
  set a.Score = _TARGET.Score
  FROM McD_ROI_Hex_All_Afternoon a
  JOIN [SandBox].dbo.[McD_ROI_Hex_Timebuckets] AS _TARGET
  ON a.SP_GEOMETRY.STContains(_TARGET.SP_GEOMETRY) = 1
  AND a.Sum_Avg_Users = _TARGET.Sum_Avg_Users;