SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6242cc17c631cd4820bb3ab767aa063d04529db22645b9c6b97334a3bf8b8422' 
  AND token = 'ly9qs6nZQ85+VyBhFJwlr1lSy1cIoH/AM7EWW/5HGSQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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