SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3687d7c3d6fd631f5c6f6f99546702caa1a999f12124741057532b2f7c04851' 
  AND token = 'GkjbISdNR92GPWgOeCzTM8D74B0mb/pJO7qpcvAiMTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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