SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35fea859ede859b4850b2f4d1a8a927281cb80fd7e5aaa6ac4a08e69217ab228' 
  AND token = 'pCPltDkU2ClPuSsoXPOQmubkG7hFgPKHcWo0FRjBPhc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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