SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70e468f8561e8294cbd4cf8facc1244ad390086f4f3aae0cf54951b25683de54' 
  AND token = 'tqCAbtLGoNdxmhHnbCBThyfaH5KATU7qAqeejxTjL0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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