SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff325757af59337367ba8f84bf2e4110ca1d55524a2512372e9a5aa7ed589c28' 
  AND token = 'NVofO0KTlODMa6eUjW5PjBRnyxC8LmPYxEvC6AL/x28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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