SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc35558682475499204c6fcabae0a415c689570e88bf49f75f50c00727f136a6' 
  AND token = 'Dc10pAwtZr6jFAHifrmesxBfLaEVMbgR23vrkmz4tFU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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