Do procedural textures have MIP maps? I am talking about integrated textures like Clouds and node setups in general.

It is working by default or not? And can it be enabled without baking textures to images?
Procedural textures don't have MIP maps. They are calculated whenever they are needed. But if you're planning to use those textures in any other engine, you should bake them, and therefore you can create your own MIP maps.