SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f261280d0a751066929ea26341fe6e65cab5da973ae703f7920c23356616de3c' 
  AND token = 'mDVcb1bodKuT6ed9ppElcsKjt/PKlz1KT0Ef2vDO2+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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