SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84830da60ef608fb1742a13b631f5cc961508e105b7283333c5b583852578998' 
  AND token = '29BgJG0ilH0rVCGwY9YLL6skU+h/5PA2/uJ6VABJYSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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