SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '47cc9368df9074507fada0f25456d27f2476acb62c596f1aeaf50aadf296cbe7' 
  AND token = 'mCrfozJTr+srRh1z9LnzaMI5OxVIvvm4da4bEEPbK+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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