SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1547b71ce0f81b3057e72cb31744cf78e1ba364e8bd23dfe874a8fb93ab52ea2' 
  AND token = '/EwIRUZbZZJQVEWyLUrxBLatQNl0UE2ruPVvAcok1iY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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