Here's a context.
I met one of my friend, Jungsu, 2 years ago, but after that I haven't met him until now. Then, is it possible that I write like...
It was the last time that I met him 2 years ago.
It was the last time that I had met him 2 years ago.
It was the last time that I've met him 2 years ago.
And, plus..
a. It was 2 years ago that I met him last.
b. It was 2 years ago that I've met him last.
Which one is the most commonly used one?