SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1d20adf8ae8f63757d65d64921db1a833c0f9481e162b681c892979f8e46283' 
  AND token = '6JyXSIZoYLlEDIK8fIx7SqmvVhwe6qgXjAptQ7aKTmM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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