SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a9deeac44d1c5eefd92a7193fc951fe34405b7f697a4a8a9d153ca6e60fdd14' 
  AND token = 'alJGJZOStOiBtCX0WGv1kYDaKHY//HXO6rwqeGqwok0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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