SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1919acd951daca4b2898a24d1bbb6564e3a5ace28382446e361f8c8de742c3b' 
  AND token = 'VpBTskSsKQUgDJeQMZOv+o2goGH6ZjAjKj++fp2P5eo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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