SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e29b8445eaffbb19300bf9b4920010ff0750b8b271aaabef33efe1efc773852b' 
  AND token = 'g13OQ6jsx3vqAdCn06ItXlqdgt8sDABnafWByweWHlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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