SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '224d4ee388285958e2f99b553de8426da302edf583e93a7d71cd59cc5c88eadc' 
  AND token = '6Fkn1Gh5zotIh9ZvLnhlUWGuCC8LeSvbDFr5VDhFbpY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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