I would say 4 hours is not enough time to leave the airport, dine and return.
I do not know of any lockers to store luggage.
There are restaurants in the airport, both outside security and gate side. You do get access to AMs lounges, there are three in Terminal 2.

There is a La Mansion steakhouse and an Italian place just outside the baggage area. As well as a Carl Jr.s on the same level near the international baggage exit, and a few small cafe type options up the escalators. If upon arrival from Acapulco you just follow the signs for baggage, you will find it leaving the baggage area. You will have to go up the escalator and back through security to catch your flight.