The Portuguese winger joined Los Blancos in a record-breaking £80m transfer from Manchester United in 2009, since which he has become Madrid's top goalscorer in history with 654 goals.
Despite turning 33 years old in January, Ronaldo is confident that his retirement will not be in the near future.
"Right now, I've got a biological age of 23," Ronaldo told reporters.
"I've still got a long time left, I can keep playing until I'm 41. I'm feeling good, happy, I can't complain."
Ronaldo will lead Madrid against Liverpool in the Champions League final on Saturday night.