24 hour automated in terminal 1 past the Burger King or Post office next to the news kiosk and Tabacco shop with "T" sign.

http://www.aena.es/csee/ContentServe...&Literal=Otros servicios

The lounges there do not have internet and as you do not have the laptop paid wifi not of interest.

You may find one still in the small shopping center near where the train comes in but long walk if you arrive to airport by taxi or bus.