<?php
require 'imports.php';
require 'lib/db.php';

if (isset($_POST['btnenviar'])) {
    $email = $_POST['email'];
    $senha = $_POST['pass'];
    $query = mysqli_query($con, "SELECT * FROM users WHERE email = '$email'");
        if (mysqli_num_rows($query) > 0) {
            $arr = mysqli_fetch_array($query);
            if ($senha == $arr['senha']) {
                setcookie("hash", $arr['hash']);
                header('location: pages/home.php');
            }else{
                $error = "Senha incorreta";
            }
        }else{
            $error = "Email incorreto";
        }
}

<?php

unset($_COOKIE['hash']);
if (isset($_COOKIE['hash'])) {

}else{
    header('location: ../');
}