SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '817e4c472df1b63fab2013b4c4b70f93cc2aac1df54a15396eb9a8ed93063802' 
  AND token = 'X//5G3pCkWuO6NjBimlj8XWqDZ7vSfsCY/9MB2XVKJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}