I'm assuming that there's two spaces as opposed to one just before artist and track.mp3. If so, this should do it.

my $file = ( $line =~ /\s\s(.*?\.mp3)\s\|/ );
[download]

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Dr. Michael K. Neylon - mneylon-pm@masemware.com || "You've left the lens cap of your mind on again, Pinky" - The Brain
"I can see my house from here!"
It's not what you know, but knowing how to find it if you don't know that's important