Well, that’s a very clumsy data structure you have there. And the code is clumsier than it needs to be, on top of that. What’s that count doing? Looks like a no-op to me. And don’t use for(;;), use for(@LIST):

for my $i ( 0 .. $#{ $self->{ keys } } ) {
    my $id = $self->{ keys }->[ $i ];
    # ...
}
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You could write accessor methods for that part of the data structure so you could say something like:

for my $i ( 0 .. $self->max_index() ) {
    my ( $key, $value ) = $self->at( $i );
    # ...
}
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Or maybe an iterator would be better?

my $iter = $self->iterator();

while( my ( $key, $value ) = $iter->() ) {
    # ...
}
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Or you could use one of the modules that implement ordered hashes, such as Tie::IxHash, which will let you write this directly using keys and friends.

Lots of options that depend on what you want to do; for laziness, the tied hash is hard to beat.

Makeshifts last the longest.