SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b43e27df47bfc0d23ed49adb28d58d56044ffa43cf7b6c60e51c25a541b0893' 
  AND token = 'IapaXqP3JnBmDWVbP9+jXvJuCi6FUsVEbuUiHyRsNtQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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