SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f36ef522d88545984b4c5068776c521aa66bc0b7d9298c6f16fb157b3834072' 
  AND token = 'sWlsSjfA532l6zSCdzz8FQ5r20FwVorHpajICJ7TgWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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