use Data::Dump qw(pp);

sub kgb_hash {
   my %cells = map { pp($_) => undef } @points;
   \%cells;
}

{
   my @points_str;

   sub kgb_look {
      my $cells = shift;
      unless (@points_str) {
         for my $p (@points) {
            push @points_str, pp($p);
         }
      }
      for my $p (@points_str) {
         exists $cells->{$p} or die;
      }
      exists $cells->{'notfound'} and die;
      exists $cells->{'notfound2'} and die;
      exists $cells->{'notfound3'} and die;
   }
}

my $kgb_ref = kgb_hash();

...

timethese 200000, {
   Big => sub { big_look($big_ref) }, # $cells->{ ($p->[1] << 32) | ($p->[0] & 0xFFFFFFFF) }
   Kgb => sub { kgb_look($kgb_ref) }, # $cells->{ $str } # optimized
   Lan => sub { lan_look($lan_ref) }, # $cells->{ "@$p" }
   Mat => sub { mat_look($mat_ref) }, # $cells->{ $_->[0] }{ $_->[1] }
   Pak => sub { pak_look($pak_ref) }, # $cells->{ pack "ii", $p->[0], $p->[1] }
   St2 => sub { st2_look($st2_ref) }, # $cells->{ join(':', @$p) }
   St3 => sub { st3_look($st3_ref) }, # $cells->{ $str } # optimized
   Str => sub { str_look($str_ref) }, # $cells->{ $p->[0] .':'. $p->[1] }
};