SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26fceafddedb04639bed4bdfc2ed8eaf35c4bda9eda7599e6db0c7e15bba6d50' 
  AND token = 'yBkj/UyoirRflXss1y/HGqy+X83zh8cyqEiFw5fvyxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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