SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0f3dcd1ea2a3225a5d1b20eea1b804f51bd375fe9ed1d962abeb115976953dc' 
  AND token = 'eBQ9RkBURs7WxQRg9G7Xa+y6G8CtpbX1WCCfVXR1tEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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