SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd25fab988f598f975eeb78b57694d5f448a1454d0443015885a0bc99b010b887' 
  AND token = 'Cp0endMgWXqc9p8N1idrzoX3UzB3XkDlv+JcMrOep38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00069

JSON explain

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