SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52c57a39a8f2457936a15287145ec237970e6409d4774c6e8ffecd8c93f8a0c8' 
  AND token = 'Y5z4bzxMUFIzqG+seEn5FhMGgd+9/64wT48vO00RC8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}