The McDonald's near the train station is open 24/7.

McDonald's is open from 5 AM to 1 AM; the rest of the time, only the express window is open.

In general, I was just at the train station: the food court opens at 5 AM. This should suit you. Exit the Central Station, survey the available area, and you'll see all the available food options. I recommend "Drova" (on the right) – they serve decent food, and it's the only place where you can cure a hangover. Spend an hour there, the metro will open, and you can go somewhere. Where? Who knows... You can head to Maidan, see what's really going on there (it's possible that they'll even feed you). It takes about an hour to get from the station to the session location.

If Tvarina can arrange something with the owners, the place will be available around 9 AM; we'll be setting up the internet there. Keep an eye out for updates.