SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38cfbba673f14284832014481696c51dc21b91bd022cd54ba5c640512870e2fc' 
  AND token = 'ZsQxKy1azQn1roCmy1yNvj/Jm+yDIMqNxpNUAnVpE2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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