SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d683253d00d1bfc51ae76ebad843527d4eccc40fd8934f0037e946188ac9b72' 
  AND token = 'oA3GiwIrdXlWDHnDIekokvHVA8naEzLRsSiBLar56NA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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