SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fc44efd02a7744fcca54f4e4d67c702d5781420ca6604a6246c99cd813df20d' 
  AND token = 'DUPE4NTRxnsSyONmDpE2ZwL0AIa1OhZCAGtvZn2SQSQ=' 
  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"
    }
  }
}