SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f48b34ed03de13f7ad7654a14baf06352a53dd011ee4434665b18762a603f0a' 
  AND token = 'BGmqVxQUGBhpXLnzS6iPjUsbdqzZsWv6BY3ix15E1js=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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