SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cf61ecbf883fd66f8bc9efc76461c7584cf0953c3d4897dd88e6c9259e8a850' 
  AND token = 'fQvO+RBA2vk7cr83N6TpXvikHFAmdhq/mRrVtv7zTw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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