SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3d9551489a7ec5373975f12632609a6965064de807576cee9ef5220e78bfc38' 
  AND token = 'UNBBne0D+NlO9u921I2JQCAnxRpGBGYTlHLvMKlpnQo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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