Or tie your hashref.

package MyHash;
require Tie::Hash;
our @ISA = 'Tie::StdHash';

sub TIEHASH {
  my ( $class, $href ) = @_;
  bless \( my $x = $href ), $class;
}

sub FETCH {
  my ( $self, $key ) = @_;
  for ( keys %{$$self} ) {
    next unless /^$key/;
    return ${$self}->{$_};
  }
  undef;
}

package main;
use Data::Dumper;
my $x = { test23 => 12, msg34 => 23 };
tie %h, MyHash, $x;
print $h{test}, "\n";
print $h{msg},  "\n";
print $h{m},    "\n";
[download]

output:

12
23
23
[download]