SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35a158a13496925a2c4455342c63231e0658de38a12aa818ae8a64d1fe911e29' 
  AND token = 'TdTHtvljsWqDkWyM6QcwX532GULrxcMIOaEY61jN7BM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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