quote

In this wiki, we will write the code to get the entity id from hashed id for Magento2 Quote

protected $maskedQuoteIdToQuoteId;
public function __construct(
       \Magento\Quote\Model\MaskedQuoteIdToQuoteIdInterface $maskedQuoteIdToQuoteId
   ) {
       $this->maskedQuoteIdToQuoteId = $maskedQuoteIdToQuoteId;
   }

then you can call execute function

$cartHash = "6zIMBpw1NSixrw8BpUzIMHOvAR9ZopYW";
$cartId = $this->maskedQuoteIdToQuoteId>execute($cartHash);