SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed4682b878225ac4cd7b7ccbe13e835c5a0b67773d946e8b353adaa842b53d9c' 
  AND token = 'sFmmwIsBRKlzuxGqZOhf0IWypqAlTb9AvHPbFkjqXbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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