my %hash;
# first open file1
while (my $line1 = <$file1>) {
    my $key = join ";", (split /,/, $line1)[1..3];
    $hash{$key} = 1;
}
close $file1;
open my $file2, "<", "file2.txt" of die "could not open file2.txt $!";
while (my $line2 = <$file1>) {
    my $key = join ";", (split /,/, $line2)[1..3];
    if (exists $hash{$key}) {
        # do something
    } else {
        # do something else
    }
}