SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a04df9da60937388559262903d1e920f51d97b0b817f586d77969e68c8553823' 
  AND token = 'thg2fwJSsm3foeuBJs9MR40MtOFxmNUYsUDtszCuWqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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