SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1d9a6a815908d6cc16dec79e2e2f02a22e9a8436bf0f78811b1811ac8f9063c' 
  AND token = '8QZ9jnY7hVWEVqkS0wv4O9Kzj5JtvvMo9z2baQDnyv0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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