SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08b476f945e1b9273c5e043c16e3ab257eee45fda28979b4bdd22aa4f89edade' 
  AND token = 'VDJ2t9oJNpbA1WLZdoSrTqj/49it2F5CjfW5GMPNXWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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