SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3a44e1db21503eb11ac1661518efeab9f18c3d6cb78974ff483a263fe9e9cd05' 
  AND token = 'BTbQaoIPpzAF5izf/1e1GykYujE4dY4ILvZwWhZTKaM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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