SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4d4add27a0a373a8b251811899234556277d95c73264f5e630558060b7b068dc' 
  AND token = 'I0PYJ7UB/WYc18wiJXgk/MhFBkHONIRxm14USimPhwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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