SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b04e16e50f1ebe1e9b3946edaf537059d7cef589d5796f95d1830a5bc657cbc' 
  AND token = 'O6tXfqgnKgthgkn6CkmGifPNTjzTFxTMYaCftiuO3VE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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