Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Medan to Greece as you normally would.
For a flight from Medan to Greece, you will be flying from Kuala Namu Intl. Medan Kuala Namu Intl (KNO) is just 23.8 km from the centre of the city.
This is defined as Medan Kuala Namu Intl Airport (KNO) and Athens Eleftherios V. Airport (ATH). Codes like Athens Eleftherios V. Airport are often used to just call airports uniquely. Heraklion N. Kazantzakis Apt. Airport (HER), Thessaloniki Makedonia Airport (SKG), Rhodes Diagoras Airport (RHO), Corfu Ioannis Kapodistrias Airport (CFU), Chania Souda Airport (CHQ) are other airports near this flight route and their unique identifiers/IATA codes.