In theory it has its own security line, but there's really nothing preventing anyone else from using it. I don't know if it's open again, but it was basically a fast-track for people who knew about it and didn't have regular fast track.
Either way, security lines in MAD are rarely more than 10 minutes even at main security. Doesn't seem to be being plagued by the other issues at European airports, but the Puente Aéreo security is to the left of main security and over a little bridge.