are there luggage storage lockers in the airport?

Yes, the airport provides this service. Both T1 and T2 have luggage storage.
T1: between Gate 4 and 5, 10 and 11 in the Departure Hall; between Gate 6 and 7 of the greeting area in the Arrival Hall
T2: near Island A and M in the Departure Hall; near the International exit in the Arrival Hall
You can easily find these places according to clear English signs in the airport.