use strict;
use Data::Dumper;

my %hash1 = ( 'key1'        => '7',
              'another_key' => '2',
              'the third'   => '8',
            );

my %hash2 = ( 'key1'        => '7',
              'another_key' => '2',
              'the third'   => "10",
            );

my @array = ('key1', 'data2');
# turning array into hash to do lookup inherently
my %array_hash = map {$_, 1} @array;

my %hash3;
foreach (keys %hash1) {
  if ($hash1{$_} == $hash2{$_} && exists $array_hash{$_}) {
    $hash3{$_} = $hash1{$_};
  }
}

print Dumper(\%hash3) . "\n";