How do I create an SQL EVENT in PHP code with parameters?

Question

I am currently trying to add 'lockout' functionality to my login system. I've done it by adding a 'blocked' column in my 'users' table in the DB, and adding a table called 'Failed_Logins' which just record the username and time of the failed login.

If a user incorrectly logs in 5 times within an hour, the account is locked for 15 minutes. The locked part works fine, but I am having great difficulty unlocking it after 15 minutes. I want to do some sort of delayed SQL query but nothing I have tried is working.

Inside my login function, I have this:

// check if user is locked out. If they aren't, carry on with login checks
        if(isBlocked($conn, $username) == 0){
            failed_logins_action($conn, $username, failed_logins_check($conn, $username));

The functions are then as below:

function failed_logins_check($conn, $username) {
    require("dbConn.php");
    // prepared statement to delete any failed logins older than 1 hour
    deletes_old_failed_logins($conn, $username);
    
    // check for failed logins within the hour
    $query = $connect -> prepare("SELECT * FROM `Failed_Logins` WHERE `Timestamp` >= date_sub(now(),interval 1 hour) AND `Username` = ?;");
    $query -> bind_param("s", $username);
    $query->execute();
    $query -> store_result(); //Transfers a result set from a prepared statement
    // save the number of rows to a variable
    $row_count = $query -> num_rows;
    
    return $row_count;
}

and

function failed_logins_action($conn, $username, $amt) {
    // for testing purposes
    echo $amt;
    require("dbConn.php");
    
    $block_user = $conn -> prepare("UPDATE `users`
        SET Blocked = ? WHERE Username = ?;");
    $block_user -> bind_param("is", $blocked, $username);
    
    
    if ($amt >= 10) {
        // blocked level 2 = perma
        $blocked = 2;
    } elseif ($amt >= 5) {
        // blocked level 1 = temp (15 mins)
        $blocked = 1;
    } else {
        // not blocked
        $blocked = 0;
    }
    $block_user->execute();
    $block_user->close();
    
    if ($blocked == 1) {
    $unblock_user = $conn -> prepare("CREATE EVENT myevent
    ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 MINUTE
    DO
    UPDATE `users`
        SET Blocked = ? WHERE Username = ?;");
        $unblock_user -> bind_param("is", 0, $username);
        $unblock_user->execute();
        //$unblock_user->close();
    }
}

It's the final IF statement in the failed_logins_action function which is the problem.

I get the following error when I try to login for the 5th time incorrectly:

Fatal error: Uncaught mysqli_sql_exception: This command is not supported in the prepared statement protocol yet in /home/devpath/public_html/includes/functions.php:382 Stack trace: #0 /home/devpath/public_html/includes/functions.php(382): mysqli->prepare('CREATE EVENT my...') #1

Can somebody please tell me how to delay the unlocking of the account by 15 minutes? In the above code I have it set to 1 minute just for testinf purposes.

I have also tried using PHP's 'sleep' method followed by a regular prepared UPDATE statement, however this did not work. If the user leaves the page during the delay, it just does not activate I think.

I have also tried 'WAITFOR DELAY' but phpmyadmin doesn't seem to allow this command. I am using cPanel phpmyadmin for reference.

I am definitely no expert in PHP or SQL so please be kind lol. Also sorry about some of the dodgy indentation.