Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Bangkok to Santiago de Compostela as you normally would.
For a flight from Bangkok to Santiago de Compostela, you will be flying into Santiago de Compostela. Santiago de Compostela (SCQ) is just 10.6 km from the centre vof the city. Santiago de Compostela is the only Santiago de Compostela airport and it handles 0 inbound flights from Bangkok per day. 0 airlines have flights to Santiago de Compostela from Bangkok on a regular basis.
These are just IATA (International Air Transport Association) codes. They are used in aviation to identify and differentiate airports. That’s why a Bangkok Suvarnabhumi Airport to Santiago de Compostela Airport flight would often be abbreviated as a BKK to SCQ flight. Bangkok Don Mueang Intl Airport (DMK), Rayong Utapao Rayong Pattaya Airport (UTP), Hua Hin Airport (HHQ) are some additional IATA codes for airports related to your trip.