SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '270d43ddcffedf93b9779eef034b8735c34fcbefba5cd68f5dc2d94a7b0a5c32' 
  AND token = 'OB/XHyosfkyZrWa8n1KRqQvyGr8plfJTElC0hD+LwO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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