SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3d1cbdc1e02f363e097cf426fb8794c958306205113bd45519da0bb9229b18b3' 
  AND token = 'y+SJdvvOQMfQt+3wb2dBnTcn/TMrE61BR8t6Jd65z24=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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