SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '456c2f9604d92e0bfd3224c6dd989e8e6a8cbb6e2b473153bb00a1d0acca60ed' 
  AND token = 'xC1AnA7bJZ5OOCACH4iAhxGnrAiwzcviuNPOpn1K+JI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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