SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5166219473d284efbca2e8a6173b5ebd50669cb41a214598fa0596396e55700' 
  AND token = 'ZD9lzrntrPIZsNyFy0HViT5PwGPcCr3+N6DgdI4nklA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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