SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03135b7dd44860c6ad540db4053a9e1c45a4256e02a27abceea47a2ab47c445f' 
  AND token = 'D3eNdBDS9jwEEFcrAk5PMGB55sl0zxMncH1mWTo8lhk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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