$ASDF{ABC}{ASDF} works (returns \%TEST2). Printing $ASDF{ABC}{ASDF}{HOHOHO} would print LALALAL.

Addition: You can do stuff like the following, too:

foreach (keys %{$ASDF{ABC}{ASDF}}) {
   print($_, ' => ', $ASDF{ABC}{ASDF}{$_}, $/);
}
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I'd make it clearer as follows:

my $hash_ref = $ASDF{ABC}{ASDF};
foreach (keys %$hash_ref} {
   print($_, ' => ', $$hash_ref{$_}, $/);
}
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