SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44804140c526810ed231f62bd0747fe63650a3474574b29806dec9f289223c71' 
  AND token = '7IV6bQO0cSNXRIbCaYOVyIKFMC85cSQziBhhcd5eBJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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