The place you’re looking for is called Kamar-Taj.
In his quest to heal his injured hands, Stephen Strange seeks out Jonathan Pangborn, a spinal injury patient who has somehow regained the ability to walk.
This difficult-to-find basketball court appears to be at the Westway Sports & Fitness Centre in London, located under the A40 highway. Thanks to a user on Reddit for posting images of this location to aid in tracking it down.
MAP
(Doctor Strange, 2016)
MCU: Location Scout 