SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f88ae6d1e618993fbda71b595f78940448e7c89a80231fd1c3d4e43c50bd498' 
  AND token = 'xAJvmkCnN1D4VwjAd47/2sFGpfHDAHIK8SlZu85MkkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}