SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0d60759f7b2b490a3bc804245ed75e15d1829c5f0129ca6ffd8f62534ce1596' 
  AND token = 'DWHZQyqa30+zjtrwxfw6VqWJlX5rQg+RdtbLiKzBjgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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