SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '780ace0edae9db42f6d094ea60f4b135b0b7b1b9ca1c192546b462ee842db5bb' 
  AND token = 'jCV3DeeZtTRKJAG+zSLCs7IKfJ87YhGzXZuQg6KwdmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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