SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c19af02cfdc204519ff6fd1e4a3147d89ba78b6f9393a2cb1c3481d9f619edf' 
  AND token = '177um27cdSTBMmJQ2M5ilzbSbfSmDTXsWHVKzQTpCzM=' 
  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"
    }
  }
}