SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '263cb003af5954a84b481f4ba8180069617df45ee5cc3e343fa193849f62f2ca' 
  AND token = '4XHqrz8TYgX1Iw6lKa58iFlDh1JsLjVA+duSZjWR4VE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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