SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39ec62e0a692619644309eb8bf681bfbd32e2a2ed022648e1398f61904454afd' 
  AND token = 'QQ4t/szqSA++sZ8B0iccZAY/90g/fOkUZq437yxY1kc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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