I captured my first personal sexual content on my android phone and - I didn't do that thing again -, then I delete it after 1 min, is it possible for hackers to reach it in that 1 min?
Sorry, don't see how anyone can have sexual contact on a phone to start with. Unless you lay on it, but that's unlikely 'cos you'd break it probably. I'm sure someone can help you. :)
I'd doubt any downloaded video is going to take your phone over.
But in any case you should be running an AV on it. Check out the Play Store for protection.