SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99942dbbef27662e122c6fe87abf4cd008c138f656c5a16a451192bf969d59eb' 
  AND token = 'W+Gq4sdojZ83Fipu8WAxPxEvJ4p7bFCwXsQFPOGf0VM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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