SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a43bc2e95e84f6637b6fab1dc393d8bfa404adc02e073a730ef3ef1aefc13e8' 
  AND token = '/K1OHso7bLopnLstUm2w73JNVGsmiN74RtgXiSBKSjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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