SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f15bf3365dd18a218601f1d5929280ad8cece623260ca2e73e0eaa1a98ab71a1' 
  AND token = 'fQM+f8/lZA5F/rbd66USqIiOloLn7uYhiq+3lFmGwqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}