SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cf4654e88bfa1b917819bd2a9f72e5cb83c02d90f4d0f2d673fc5bfe4f18e47' 
  AND token = '+fNvOiuoASwzwqZRJSlmSjqESahz1DJI/PteXxiKuC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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