SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fc38cc0fef5aa860a8b3a3a06d33e0df7a777acb95d75f33665ccb7e6d23af4' 
  AND token = '9ETnfu7GpEs13y8LTpekgie0hWVAQQIweyX9vg67vEc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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