SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '493059c35f92ee20921465f7af7f59bf547e953944b17760a7178bccd5a75b99' 
  AND token = '6yRv0OT4U+fiwnELEeBKiqqgPiZASZdZVPFM67iHT0A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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