How validate an array? (Laravel)

How can I validate this array in laravel validation:

"price" => array:1 [▼
           0 => array:1 [▼
                "price.value" => 50
]

I tried to use this, but it does’t working:

'price.0.price.value' => ['required']

How can I solve?
I want to note that: I have no choice to change the name “price.value”.