Flight Soekarno–Hatta International Airport departs from Jakarta Soekarno–Hatta International Airport at 19:50 and arrives at Kuala Lumpur Kuala Lumpur International Airport at 23:00.
The flighttime is about 2h 10m. The distance travelled ("as the bird flies"): 600 Km. So the average speed is roughly 277 Km.
There is an 1 hour time difference between Jakarta and Kuala Lumpur