SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '602b20d5b753395f2ed1aeb049c7314939ffb5b7eddf0590fe0e6a0e98581fb7' 
  AND token = 'K4Q9QUE3u7M5ZgwvRtLuJQPLQAv5jiyn5aPEV/KvYRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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