SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8caf8e719a1aa451c06fd9ffba3c1f32969360445ec0dcd65081ba6ee4cffc55' 
  AND token = '1BJ7H253cxIqFM79tE6ud0SsA4VqsPRof3JExHAtUcA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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