访问cookie的数组位置

I was doing a simple php code and I found a problem. I would want to access to the value of a specific position of a array of cookies, but I don't know why, I tried to use:

$value = $_COOKIE['conexio[cont]'];

But It doesn't works. That's my code:

<?php 
    if(!isset($_COOKIE['conexio'])) {
        $valorinicial = 1;
        setcookie('conexio[cont]', $valorinicial);
        setcookie('conexio[data]', date('d-m-y  h:m:s'));
    }
    else {
        $value = $_COOKIE['conexio[cont]'];
        $value = $value +1;
        setcookie('conexio[cont]', $value);
        setcookie('conexio[data]', date('d-m-y  h:m:s'));
    }

 ?>

You can read the data by reading the whole array and access the desired index afterwards:

if(!isset($_COOKIE['conexio'])) {
            $valorinicial = 1;
            setcookie('conexio[cont]', $valorinicial);
            setcookie('conexio[data]', date('d-m-y  h:m:s'));
        }
        else {
            $cookie = $_COOKIE['conexio'];
            $value = $cookie['cont'];
            $value = $value +1;
            setcookie('conexio[cont]', $value);
            setcookie('conexio[data]', date('d-m-y  h:m:s'));
        }

    //create array for cookie
     $std_arr = array(
                    'index' => 1,
                    'id' => 5,
                    'name' => 'jony',
                    'class' => 'class-8',
                );
    //ready cookie data
     $cookieData = array(
                'cookie_status' => 1,
                'data' => $std_arr
            );
    //create final cookie array
            $cookie = array(
                'name' => 'std_record',
                'value' => json_encode($cookieData),
                'expire' => 86500,
                'secure' => false
            );
//cookie st
            $this->input->set_cookie($cookie);
//cookie data retrive
    $cookie_data_retrive = json_decode(get_cookie('std_record'));
    print_r($cookie_data_retrive->cookie_status);