Hi @Kamil_Hurajt,
now I get you. No worries. 
The best you can probably do is to use the Multi Search API and issue one query for index1 and one for index2.
And to take a step back: I do not know the larger context of your application but based on your description I am not sure whether Elasticsearch is the right solution for your problem in this case (I don't know which other features you use).
Daniel