{ a => 'b' }->{$k};

##</code><code>##

my $hash_ref = { a => 'b' };
# and then
$hash_ref->{$k}

##</code><code>##

use strict;
use warnings;

use Benchmark qw(cmpthese);

our $global_hash = { 'a' => 'A', 'b' => 'B'};
my $lexical_hash = { 'a' => 'A', 'b' => 'B'};
use constant CONST_HASH => { 'a' => 'A', 'b' => 'B'};

cmpthese(-2, {
    'hash' => sub { for my $x (qw(a b a b a b)) { my $y = { 'a' => 'A', 'b' => 'B'}->{$x}; }},
    'global_ref' => sub { for my $x (qw(a b a b a b)) { my $y = $global_hash->{$x}; }},
    'lexical_ref' => sub { for my $x (qw(a b a b a b)) { my $y = $lexical_hash->{$x}; }},
    'const' => sub { for my $x (qw(a b a b a b)) { my $y = CONST_HASH()->{$x}; }},
});

##</code><code>##

                Rate        hash  global_ref lexical_ref       const
hash         27571/s          --        -73%        -74%        -76%
global_ref  102819/s        273%          --         -3%        -10%
lexical_ref 105720/s        283%          3%          --         -8%
const       114361/s        315%         11%          8%          --