my $found = 1;
  my $cursor = $hashref;
  for my $key ( qw/$key1 $key2 $key3/ ) {
     if (exists( $cursor->{$key} ) {
       $cursor = $cursor->{$key};
     } else {
       $found = 0;
       last;  // NOT FOUND - QUIT LOOKING NOW
     }
   }
   . . . 
   if ($found) {
     // $cursor REFERS TO THE ELEMENT THAT WAS FOUND ...
   }