SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d0f755724bb8bc91445cdeee14acad14b16c5245718982379cb98080c1b0382' 
  AND token = 'DMobv5+ib/im/pYQhAjLnwzd2IYAHtrvElTovued/Zg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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