SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5efd2abe87131a458516b9ea5f13ee957b835c041d9fcf3eec4d53b1401236d8' 
  AND token = 'IC8UUQQ88ewOQw+6xBxSsGofwVCBu0OwMImDsUaog6I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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