SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef34f7cf94db62336ebdf756b0a4f1eee39a706d14359fa05ca3bef146c3cb7f' 
  AND token = 'qaGzQTazKoEf0wKmj5t+BTCqx+ifVjM+KI/LKOnWuoU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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