BasketProperties::get

protected function get(BitrixSaleBasketPropertyItem $basketProperty, array $fields=[])
{
	/** @var BasketPropertiesCollection $properties */
	$properties = $basketProperty->getCollection();
	$basketItem = $properties->getBasketItem();
	/** @var Basket $basket */
	$basket = $basketItem->getCollection();
	/** @var BitrixSaleOrder $order */
	$order = $basket->getOrder();

	$basketItems = $this->toArray($order, $fields)['ORDER']['BASKET_ITEMS'];
	foreach ($basketItems as $item)
	{
		foreach ($item['PROPERTIES'] as $property)
		{
			if($property['ID']==$basketProperty->getId())
			{
				return $property;
			}
		}
	}
	return [];
}