If the scene camera keeps moving after you released all keyboard keys, this is a fix for you. In fact, it is a fix for everybody as this also makes Unity run faster when moving in the scene.
When pressing a keyboard key the operative system repeats the key press many times.
Unity decides to queue all of those repeated key presses when moving in the scene view and generates several "slow" events
that trigger OnGUI Repaints and more. So many events that the queue keeps growing if the computer can't process all of them
fast enough, to the point of keep moving after long after the keys have been released.
Events that get queued until all of them are performed. If your computer is not fast enough, it means that the editor will keep
on executing those key presses long after you stopped touching the keyboard.
This scripts changes the Windows settings of the keyboard, slowing down as much as it can the settings of key press repeat speed,
while moving on the scene. Then restores the previous settings.
Copy paste the contents of the folder FixSlowSceneViewMovement anywhere you want inside the Assets folder of your Unity project
Only works for Windows users. It should work on Unity 2017, 2018 and 2019.