SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9d896b309cd2f80a61ee8fa6648ffb3d114658b402462706c71c1f1d1ebde61' 
  AND token = '0dsTjbDqDZnmkGAVhag2dyq1ktdFjVVAjMruP+6Fji0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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