SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74ddf578678da08a643475ef1722f77a949cf176ccb247e2ff020b13c2600724' 
  AND token = 'LCE/uwyJUKipmy0YZgz0IGoJEUNZSgQL3Dsf+PQg4Pg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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