SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '03a14833f52aba2ead71023a8bffdc67e688a6c8c514a98f127820fb2354b02c' 
  AND token = 'XmllnDtLJ4ZBctjoV5yDnh1P0CqAldoq9uy66Q/yRzk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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