SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca8f63af0df42ce42b411f9d609ab941c8f8d6c93d29200db714c6d32959a589' 
  AND token = '7bScWx1dukuk2E3SUBC2m7UGd7hFW+bPy+ZVfgBHLFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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