SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a244fc4d169308c2bb291e1510fdd19a04e2ea8078280c6953595a7046cdeddb' 
  AND token = '4S/MQrUBjgTmLNiPlKYDuY+kDzksKkvZ6Utaq20qwkk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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