Untested code:

use 5.010;
my $hash = {
    array_key  => ['one', 'two', 'three'],
    scalar_key => 'four',
};
while (my ($key, $value) = each %$hash) {
    foreach my $element ("ARRAY" eq ref $value ? @$value : $value) {
        say "($key, $element)"
    }
}
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