existsr.pl

sub existsr (\%@) {## no critic
    my $h = shift;
    for my $k (@_) {
        return !1 unless exists $h->{$k};
        $h = $h->{$k};
    }
    return !!1;
}

my %h = (
    aaa => {
        bbb => {
            ccc => "ddd"    
        }    
    }
);

say existsr %h, qw/aaa bbb ccc/;