SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '49a17b887dcb74b26b1a72714d1ebc4b0e2972ba0254c29fca2dc5b8bacda769' 
  AND token = 'KPPJCEqoNVG+j9YEQmmHfV9hFv3ObDwMA2vpNJiWlMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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