SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae939e174909746d7b8c13e2f980d9acff331bff421a8b426a0d4f03982dd422' 
  AND token = 'gXBiuJBZNCPpHGHl3GwI8rVlmWBRxbjiPIQQtcfUMNQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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