my $id2=1;
my %data=();
foreach my $id (keys(%hash)) {
  foreach my $key1_val (@{$hash{$id}{'key1'}}) {
    foreach my $key2_val (@{$hash{$id}{'key2'}}) {
      $id2++;
      $data{$id}{$id2}{'key1'}=$key1_val;
      $data{$id}{$id2}{'key2'}=$key2_val;
    }
  }
}