SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '917aad37aa6d3569d2121b334d810d04c952f5f7064ee5b6f74596f729464dae' 
  AND token = 'XA8WZRU/szDqmaBMX6vnHZI5HDvDmGQjyNvQl7F7k/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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