SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '07d76c7dbdc2061347a0ead9b0570f99ad5f9e244708f1ef3115459130876f42' 
  AND token = 'lVMhMU11Bg+5HUxrTg9f/Ajxwg0YIyEKAYAzQo6gtvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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