SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '116d590597aeb9bdb90fecb4639195d59bf0caaf8f789fa69a4eb069bc19c623' 
  AND token = 'Xv8mO9Hjh5HaTRUX1YwgifXN7JpbIiuUxr3zjGsfE7A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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