There's other footage of Mike playing keyboards (the "Our Team" video from M.I.U.) but it's doubtful he played very well...and given every other member of the band could play keys, there'd be no reason for him to do so. Add to that Mike's general dislike of the recording process, and there's not much reason he'd be around for tracking.
Which song does he play on? I like MIU a lot and have always wanted to see the Our Team promo video.