James Doohan was 61 in Star Trek II: The Wrath of Khan when he played the character 'Montgomery Scott'.
That was over 42 years ago in 1982.
In 2005 he died aged 85, starring in 32 films in his career, 21 of those after Star Trek II: The Wrath of Khan was first released. If he were alive today he would be 104.
In Star Trek II: The Wrath of Khan, I think James Doohan looks: