How to blocked login for few minutes after 2 unsuccessful login attempts?

You can block users for few minutes if they continuously try to login with incorrect details with the following code:

<?php
// your login file where the frontend code you are using...
        $msg='';
	if(isset($_POST['sub'])){  
//If login failed	
		if(isset($_SESSION['num_login_fail'])){
		// check the number of login failed
		  if($_SESSION['num_login_fail'] >= 2) // you can change the value of login failed
		   { //if number of login failed greater than Or equal to 2
			   // Check the time if 10 minutes done or not...
			 if((time() - $_SESSION['last_login_time']) < (10*60) ) 
			  {
				 // alert to user wait for 10 minutes after
				  $msg="You have incorrectly typed your password 2 times,
					try again after 15 minutes.";
			  }
			  else
			  {
				// after 10 minutes
				 $_SESSION['num_login_fail'] = 0;
				 $msg= admin_login($_POST);
			  }
		   } 
		   else{ // if number of login failed less than Or  not equal to 2
				$msg= admin_login($_POST);
			}
		}
		else{
			// if number of login failed is not set
			$msg= admin_login($_POST);
		}
	}
	echo $msg;
?>
<!-- Here include your function file -->
<?php session_start();
include('dbconnect.php'); // Include your db connect file here

// Here is your login function

function admin_login($data){
    $user=mysqli_real_escape_string($GLOBALS['connection'],$_POST['username']);
	$password=mysqli_real_escape_string($GLOBALS['connection'],md5($_POST['password']));
	
	// Your mysqli Query...
		$login="select * from register_user where username='$user' and password='$password'";
        $query=mysqli_query($GLOBALS['connection'],$login);
        $result=mysqli_fetch_array($query);
        if(mysqli_num_rows($query)>0)
		{
		  // If user details correct, get the User-Id in session and redirect where you want to do...
		  $_SESSION['id']=$result['id'];
		  echo '<script>window.location="home.php";</script>';
		}
		else
		{
			$_SESSION['id']="";
			$_SESSION['num_login_fail']++; //Get the number of login failed in session
			$_SESSION['last_login_time'] = time(); //Get the time of last login
			$msg= 'Username or Password is not Correct....';
		} 
    	return $msg;
}
?>