SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29c225df71f4bf7cecf6ad24a0698e470085ed5f263f1c182bf3322d8df0b616' 
  AND token = 'AUi17pz9krjm+/UwQytuE9MkKVSlOyYVdAs+XF11VXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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