use Fcntl ':flock';
my $file = 'file.lck';
open my $lfh, ">>$file" or die "Can't access $file : $!\n";
if (flock $lfh, LOCK_EX){
  sleep 1 while (time - (stat $file)[9] < 1);
  #
  # Send your Amazon requests here
  #
  utime time, time, $file;
}else{
  print "Can't lock $file: $!";
}
close $lfh;