SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cb13733625d3f1499aebc7cda046a8e89e9889a83fcd96eda058ab948933922' 
  AND token = '+AGsLubc9hQV8/sjSfbCdWdLsvUzbe+2wVc+3lxcduM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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