SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf7249d58ba6514cbaf00b37f54cb4bf2f7f79d342a1651cecf5fd352cd4c4dc' 
  AND token = 'V0wzORZDXEdHKE5VK+wG+pnmnfOh8O3zZgiwpM3Zlhs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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