SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c39c586c8fecc7d5c0bc02f009de7766ebfcb3d5793cec253dbcd0979159d8c0' 
  AND token = 'EqJea/wesNKVg3U8vnODoZS0BpZvCvWBmpZ6ys4VTnc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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