mysqli prepared statements

$filepath = $this->storage_path . 'marketing_opt_out.csv';

$status = Subscribers::STATUS_READY_TO_IMPORT;
$importInto = Subscribers::IMPORT_INTO_DM;

$lookupStmt = $mysqli->prepare("SELECT id FROM orderwise_subscribers WHERE orderwise_id = ?");
$insertStmt = $mysqli->prepare("INSERT INTO orderwise_subscribers (
    orderwise_id, subscribed, email, status, import_into
) VALUES (
?, 0, ?, 1, 1)");

if($fp = fopen($filepath, "r")) {
    $y = 1000;
    while ($csvLine = fgetcsv($fp)) {
        $lookupStmt->bind_param('s', $csvLine[1]);
        $lookupStmt->execute();
        $result = $lookupStmt->get_result();
        // // No record exists
        if($result->num_rows === 0) {
            $insertStmt->bind_param('ss', $csvLine[1], $csvLine[0]);
            $insertStmt->execute();
        }
        if($y % 1000 == 0) {
            echo "<pre>", print_r('memory usage : ' . memory_get_usage()), "</pre>";
        }
        $y++;
    }
    fclose($fp);
}
$lookupStmt->close();
$insertStmt->close();
$mysqli->close();