SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '178cf4219fe7058ab38c95532793d0a7c71cc71b4abe7f965a98209826f04321' 
  AND token = 'WTJ34RzCtI1wZHg2KPiUrKTKf+IDPrU5xgP64oxJChs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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