SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97a89536ad4da6dc2a9ac8d42e899af2f9386f2eadb2cf11c7a08cd1ed2e21a7' 
  AND token = 'LBn6di5HDHr8daaJ0ot/fWdimiCX7bzKDwpVSPozzgI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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