SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efb38132068bff02323a0f7d6cf26e3bff9d6bdeb06d66a9bf0f5625b2a1ad72' 
  AND token = 'feL6tRfDDau2GfeUxFotJ22Ttk+vOpUwv99Zeguv4As=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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