SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '355b5264ff51ec6fca3e3210c6f8d85b1923447a81c4303c8fdf888e56d4ab24' 
  AND token = 'FAiI/T8KjYcHbQzMhlXndtZa4xJbN+abuF0GrrP2o/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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