SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4bfd5c17c71d6f7707965545870e740484a9f2104ecda457f44ac56de72aa4ab' 
  AND token = 'SI/OZH9VNZbRyDzzusZye7yx+zZxHo8BCggBTSRe2v4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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