SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56835768ad642cae3148c44ef2ffefb6d54c899b06d98ccc7d89eef481e7c872' 
  AND token = 'qFMABrCB+FE/YQ/RLQWl04jtsup9WN+evY6kH38Itsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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