use strict;
use vars qw($hashRef1 $hashRef2);
#code that puts values into the hashes

my @keyIntersection =
  grep exists($hashRef2->{$_}), keys %$hashRef1;

# Or if you just want to know if there are any

use List::Util;
my $hasInt =
   first {exists $hashRef2->{$_}} keys %$hashRef1;