SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '935e845c7ceb52a57d3295354d6e36a19e1cf236d75de36ff615fbf8a3b89da5' 
  AND token = 'JPp6LTzjxdvb8kXVfLz2zi1X0tGZhMQjCh7FtNNy/Vw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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