SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '815a031c5faf7d6bf404bd4b0ac9e5273230b9d85c06cbed99142dfa7a1dec43' 
  AND token = 'UKgJopsqZOzy7k6pQgXJWYV3ETmYIYwVxh3hqLIkK8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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