SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64831f8dc891ecd7cbcf1201e6126b1d265a03efd41e101451359e78cd7d66cc' 
  AND token = 'WtKWH94QMjsLxKPdPbrYpNfoeYOD1ECqJrdHn4qyDX8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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