You are correct that Arsenal will have an easy way winning that match. Although Luton Town was promoted to the Premier League, they are still playing very poorly, and I don't think they can avoid dropping back to the relegation zone with their current performances. Arsenal will undoubtedly win this match in order to secure their place at top of the league. However, they will face tough opponents in December, including Brighton, West Ham, Liverpool, and Aston Villa. I find it hard to think that Arsenal will be able to defeat the four clubs given that they still have one Champions league game left to play. They can win like two out their next four premier league matches.
Anything can happen in a football match, but Luton town against Arsenal, there's no doubt that Luton can compete with them, especially at home. Arsenal will still find it easy to win the match.
The match between Arsenal and Luton is more like a walkover for Arsenal because Luton has really not woken up to realize that they’re in England’s top flight league, they still play as if they’re in the Championship. This match will be a boost to Arteta and his men especially as they’ve got some tight and crazy fixtures for December.
Though Luton could pull some surprises as football is a game of 90 mimutes but Arsenal has the upper hands and would come out of this encounter top. They're currently at the top the table and that would build their confidence level to do better and maintain their position in the standings, I feel sad for Luton cause they'll get it hot from Arsenal, the match could probably end with Arsenal leading with 3 goals or more.