Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Mauritius to Kolkata as you normally would.
Kolkata Netaji S. Chandra (CCU), located 13.4 km from the city centre, is the airport you fly into when you book flights from Mauritius to Kolkata.
These are just IATA (International Air Transport Association) codes. They are used in aviation to identify and differentiate airports. That’s why a Port Louis Sir Seewoosagur Ram. Airport to Kolkata Netaji S. Chandra Airport flight would often be abbreviated as a MRU to CCU flight.