SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd858d096350801a87d1d22de00011f27a973afeaab027cee571250be58b8895d' 
  AND token = 'vi0+gNsJtiWmCu6ICevjA9ZGGXXGJQWZH06iGjWXVXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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