SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e654923479dc23adab91708b8ba0d8239742fd628a91f3ad561c4a903dbeee9' 
  AND token = '+KRL+eHeHVui30Ngz7mpWJMZw7PQVGr3UQj66KLin9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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