SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '825febbc39a3482321146d3af219cfeaebf9b6dab95e61d248585300385dc516' 
  AND token = '0MjFA1A014EL0TvtOPQlODvbk81pWpQFFv77+8y7WhY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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