SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '477a58efb5721890c211aa831c60c71bae3cfa0c0482fee7dcdab6740a386ce3' 
  AND token = 'nkVKHC+NmScOAs6DAzKCdBigHAuHqEmmcC9UIIQuTYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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