use strict;
use warnings;

use Set::CrossProduct;

my %hash=('ID' => {
                  'key1' => [ qw/ key1_val1 key1_val2/ ],
                  'key2' => [ qw/ key2_val1 key2_val2/ ]
                  }
          );



foreach my $id ( keys %hash ) {

    my $keys = $hash{$id};

    my $set = Set::CrossProduct->new( [ values %$keys ] );

    print join( ', ', $id, @$_ ), "\n" while $_ = $set->get;


}