SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a944c44bf1b2ba8245d6ebf422989ae0f8c20e654b12b99660faec526d07c6fc' 
  AND token = '/NaHhEvJuPpt9ytTnfvBMcs7ZXxcoAc7aksaWHgA9Nk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}