SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a283e462dfe8be873afca89809781f54fee7193b1e487e4b6cf81e491c980dcb' 
  AND token = '5YIWvhmzlOx0q/u4+54NQZG6vuXQpnfdOY+XXuadqwI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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