SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b6020ec81d5f813742af5578ca8dae0ca0f61e4ed4721bfbce6422ab0adc918' 
  AND token = 'C8FyMusvdIGYbVOxUfJPmhkdthq4PQmFwXzkr2as0y4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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