It depends if you want to go to the city. A one way by train from the airport to the city takes 28-32 minutes (28 minutes from Terminal 1 for MH and 32 from Terminal 2 for AK). If you want to go to the city, have a meal and head back, take AK867. I would check the OTP for both flights and decide. I'd take AK867 as I have AK869 as a backup in case AK867 is canceled.

Assuming you are out by 1545, schlep over to T1 to check your bags if any, and head back out to the city, you should be in the city by 1700 at the very latest. You can stay in the city and take the 2100 train (train runs every 20 minutes) back to the airport and you'd arrive 2 hours before your flight.

AK869 is neither here nor there although there's a small shopping mall where you can kill sometime next to T2 if you are into that. Get a Thai massage etc. You can also take the train to Putrajaya but that train runs less frequent than the one to KL Sentral. But the Putrajaya station is somewhat in the middle of nowhere and not close to the main putrajaya center.