SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5be9a1c7aba9737c5b69f0384f705b5893a250d90614931ffea2273ad9c33318' 
  AND token = '/NdzNxIPuaVxgHjDtPrDc+cZ6kCvBNMqjM/L2AYWr78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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