my %hash; # hash of hashes already defined and filled in an earlier part of code

foreach (sort keys %{$hash{$key1}}){
    if ($hash{$key1}{$_}=~ /^.+_(\d+)_.+AAA/gi){
    print "found1\n";
    }
    if ($hash{$key1}{$_}=~ /^.+_(\d+)_.+BBB/gi){
    print "found2\n";
    }
    if ($hash{$key1}{$_}=~ /^.+_(\d+)_.+CCC/gi){
    print "found3\n";
    }
}