SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '624011e33e595a7f84fa5b0eb46c312e5955e823a6c985fce9383b8372940d47' 
  AND token = 'h86XXkUheOnYqPTS/1WCdfhFRjL8BEmG3k1tVJmiakU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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