SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '38639e4d53afdebae5350b7fc79af4e8f4ff97cdcea72f2422300767c82f2b43' 
  AND token = 'OGVtEWNlmgMs+VrlwPOhKH4FolbL7inf1ERp0xEQilY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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