SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e2ef1e916ce3216bd3816945019c35818553dbd500b4ffe4b757020eccbc5d7' 
  AND token = 'WmNvwu+3ruwtPN8MkKtxRaMTzJPoeJL7lISC7aomR5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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