SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd758655b7b39cf0365e060ef863153ee80b23dee3a3e358c5290689e457c291c' 
  AND token = 'xqTL6CsoRblrBu7NZZmPsFbMDBpQ+qmq3pplNrcRtoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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