Parameterized queries

<SNIP>
  $username = $_POST['username'];
  $password = $_POST['password'];

  $query = "SELECT * FROM logins WHERE username=? AND password = ?" ;
  $stmt = mysqli_prepare($conn, $query);
  mysqli_stmt_bind_param($stmt, 'ss', $username, $password);
  mysqli_stmt_execute($stmt);
  $result = mysqli_stmt_get_result($stmt);

  $row = mysqli_fetch_array($result);
  mysqli_stmt_close($stmt);
<SNIP>