SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35d2eeefb1766a5c394f7f95c2fc27c49bbe36c0a11b6b4415a715c6e4084bce' 
  AND token = 'BvG6WQvycPP0JPgdKtgIJwl/+a2SkaM+jjYq0BqQWxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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