$dbh->begin_work;
my $channel = $dbh->selectrow_hashref("SELECT * FROM data WHERE ToScan IS NULL AND title IS NOT NULL limit 1 FOR UPDATE SKIP LOCKED");
my $ID = $channel->{'id'}; 
my $title = $channel->{'title'};

# $dbh->do returns the number of rows affected on success or undef
# on failure, so you need to use defined-or (//) here instead of a
# regular or (||) unless you want "zero rows affected" to be
# treated as a fatal error.
if (defined $ID) {
  $dbh->do("UPDATE data SET lock=1 WHERE id=?", undef, $ID) // die $rsth->errstr;
}
$dbh->commit;