如何设计一个安全的MySQL表结构来实现密码重置功能？

CREATE TABLE password_reset (
  id INT(11) NOT NULL AUTO_INCREMENT,
  user_id INT(11) NOT NULL,
  token VARCHAR(255) NOT NULL,
  expiration_time TIMESTAMP NOT NULL,
  creation_time TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (id),
  FOREIGN KEY (user_id) REFERENCES users(id)
);

function generateToken() {
    $length = 32;
    $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
    $token = '';
    
    for ($i = 0; $i < $length; $i++) {
        $token .= $characters[rand(0, strlen($characters) - 1)];
    }
    
    return $token;
}

$userId = 123; // 用户的ID
$expirationTime = date('Y-m-d H:i:s', strtotime('+1 day')); // 链接的有效期为一天
$token = generateToken();

$query = "INSERT INTO password_reset (user_id, token, expiration_time) VALUES ($userId, '$token', '$expirationTime')";

// 执行SQL插入操作

$token = $_GET['token']; // 从URL参数中获取token

$query = "SELECT * FROM password_reset WHERE token = '$token' AND expiration_time >= NOW()";
// 执行SQL查询操作

$newPassword = $_POST['new_password']; // 从表单中获取新密码
$hashedPassword = password_hash($newPassword, PASSWORD_DEFAULT); // 新密码进行哈希处理

$query = "UPDATE users SET password = '$hashedPassword' WHERE id = $userId";
// 执行SQL更新操作

$query = "DELETE FROM password_reset WHERE user_id = $userId";
// 执行SQL删除操作