Los Blancos, who were close to signing the Spanish international in 2015, have been linked with a second move for the United stopper this season.
De Gea, who has 14 months left on his current deal at Old Trafford, added that he is only focused on helping his current employers to silverware.
"Time flies by so quickly. I've been here seven years and I am happy," the 27-year-old told the Sunday Star. "A lot has happened to me - some very good, some not so good, - but to be honest I am just really happy.
"I feel like an important player in the dressing room. I am one of the oldest in the team. It makes me happy to see the younger players coming through - and trying to make United big.
"I don't think it's ever good to discuss the future or what may happen. Only the present, feeling well, playing well and helping United is important."
De Gea moved to Manchester from Atletico Madrid for £18.3m in 2011, and has made over 300 appearances for the club to date.