SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3028fd684864df5e32b3255107811662ce6dddd3a766d99bfb16e14df2e9240d' 
  AND token = 'vWUuVZ3YWSd3lL8WxwrPlNhAzSKbN1pwAQLb3XU9crs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}