SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '559e7fe95cd308b02c0deda76c002e8786efe723b5c6eef828eed2a3fa5106da' 
  AND token = 'UXhRKIfCZQNPXPc63UKybX6E28eW28eLG2Eo+xiq7k4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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