SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88125c8ab7cc719e99c53a69afe192ef4d89ce26694c0ee0977a2684f2c39775' 
  AND token = 'cqchScKy8U4ffwnBwT5p4a+WDEHuWThAK7faYXsLTvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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