SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd55977b62f523c14d611697027b54cd4ef2f0df12e272a19ff0a765b79d1601a' 
  AND token = 'Gkp0U7aQmFi98ytlKW7CoMD9Vlba4h9GhKHuWGOWSwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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