How to optimize slow query with many joins [closed]

Answer 1

Is you SQL faster without this?

Round(3959 * Acos(Cos(Radians(51.465436)) *
  Cos(Radians(vehicles.gps_lat)) *
  Cos(Radians(vehicles.gps_lon) - 
  Radians(-0.296482)) + 
  Sin(Radians(51.465436)) * 
  Sin(Radians(vehicles.gps_lat)))) AS distance

performing math equation is very expensive

Maybe you should consider a materialized view that pre-calculate you distance, and you can select from that view. Depending on how dynamic you data is, you may not have to refresh you data too often.