SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c61845ff7a9be938a11cd57707a971bfc533a2510ead5366f8a923b0d081575c' 
  AND token = 'wPRyIIuIOJ99WQR1KDj/lEOLkROuuPeZLlE+LveRcb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}