my($q1,$a1) = split(/=/);
$prod->{$environment}{$dbname}{$q1} = $a1;

        my($rt,$ap) = split(/=/);
          $preprod->{$env}{$database}{$rt} = $ap;

and then comparing the values as

if ($preprod->{$env}{$database}{$rt} ne $prod->{$environment}{$dbname}{$q1) {
print "$preprod->{$env}{$database}{$rt}\n"
      }