SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f1d5ae24d4708e1589a2ed76ebb7491f3dc682f8ade684856aac7ad91de97b6d' 
  AND token = 'dw0cTd1NkrVhTO4rrZz4XfGiVdqhPIsICAykrIzPOb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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