SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fcab9001d6e19f2bdbe58b129081515449b826efa6ec8953e6e32eaa722f3859' 
  AND token = 'SnVA+pVXLai1kBj95umxdAwpFe+kvJKLu/mdqrKtUz4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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