What doesn't work about it? It seems fine. I tweaked it a bit to demonstrate:

%h1 = ( "key1","value1","Key2", "value2" );
%h2 = ( "Key3","value3","key4", "value4" );


# Declared two hashes

%hoh = ( "key1" => \%h1, "key2" => \%h2 );

foreach $key (keys %hoh) {
   $innerHashRef = $hoh{$key};
   foreach $innerHashKey (keys %$innerHashRef) {
      print "Inner Key: $innerHashKey\n"; # this does work
   }
}
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