It is from the movie "Something's gotta give". The script is http://www.script-o-rama.com/movie_scripts/s/somethings-gotta-give-script-transcript.html
The following is the full sentence.
I'm saying this because for two people convinced they've got life beat, there was something cooking in the kitchen other than pancakes.
I think the word 'beat' is used as transitive verb in past particle form, but I could not figure out the correct meaning of the 'beat' with regard to the word 'life'.
is just an idiom meaning "they are doing well". It's that simple!
It's hilarious why anybody wouldn't understand this simple metaphor, you'd think people spoke different languages or somefink.