SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '03b96e3ce48868285adbb7606ea3c2fb74899183c6470b56abfa59278bc67ee2' 
  AND token = 'B/jBgJ/jUEonHGaZACG2PCGpvFMleVC7cFMJpR4kwns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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