SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3c9010d68261036217cee6219e17d55c41df3317352288fafbaff8fed085b007' 
  AND token = 'B3RjtpnJQ9PZiTaOneQ51A5F7sj6bpzNyX4MNOmbYMs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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