SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3dbc56c7584a7c360b1f094397013a483db5e223f96322a83b79e84f05fb4656' 
  AND token = 'yAtIx51EFoDfQiEuN4/kWhOzMR9JBRXZHmvwgyYOiB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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