Did not find any information if Unity does collision “culling” automatically or do I have to write my own code. Something that checks if it is even possible car to hit some mesh collider bounding box, and only after that check actual collision with mesh.
Unity (probably using PhysX) already does that by calculating collisions between every objects’ Axis-Aligned Bounding Boxes (AABB) and then only calculate mesh collisions between meshes which AABBs are intersecting.