SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71dd4f93cab2ea1f544cc002f461a07238f54984bd43f2a10cdde72f2bf203e8' 
  AND token = '0ZgPESfz9cwgxZDak9w4h6IC8gvLqqF3YjIHQAXJLvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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