SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e88406692d243aa2bfe4d6146d07864397bb143d5dd5a4b93f7faee6c1ad0491' 
  AND token = 'vitnrl4ymXaXs5r2t2uuRmip5+wUTX5d7g8sS2ZDXyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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