SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '056ff8e561c85a91a08441acfc1be60b578a9d0bb2740fb0ec16ff713b4b2eac' 
  AND token = 'LXPWoWKd2JeeAGJSmsjYat7CrWPGv14GSoKVNB7Nbjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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