Lounge in Trivandrum Airport

Hi All, Travelling back to US with an 8 month old in January. We are taking the TRV-DOH Qatar Airways at 4am. We do not have Indian credit/debit cards. Since we are traveling with an infant, is it better to avail lounge facilities? Like feeding/diaper changes/relax etc? How crowded is lounge at 2-4am? How can we pay without Indian cards? How much INR for lounge access without cards?