SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2895b9b6d3c0c3ef1dd64540780ed68dd3226d83bcd4d6a47d4317d2e0f48347' 
  AND token = 'onFwr6aKum22mjIDGEDKrtvOunhQIfITkmUpRXkyRVE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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