SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1433080c2a48b46a02c9136ea058d22e2df111810dccb35d94e975a159a4936' 
  AND token = 'znOA++tZlqz3pP3fuCMUeUl+Y5zaBP/4at+1/snPK40=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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