Does the Micromax Spark not support Pokémon go?
Solution 1:
The phone probably doesn't support the game. Is there a reason (besides that it might'nt be available in your country in the Play Store) why you downloaded the game from APK Mirror?
If it's not available for your device in Play Store, then your phone could crash due to overheating while loading the game.
Solution 2:
Adding a little more detail than "The phone probably doesn't support the game."
Your phone does not meet at least one of the suggested requirements of a "Preferred resolution of 720x1280 pixels", since the Micromax Canvas Spark has a display resolution of 540 x 960 pixels (source).