SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9542a9ba42d28100e8617d5acc343f86109665cc8ce574a3c7bd9b3e88c4ad13' 
  AND token = 'b8sqpHwBuoe+g5VoEWTyDd2nDwXg+2DjcxdO1Vb6VKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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