SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43dd2f46444a0c565e02ae30edb777b66b911247d540e69ac53de0f5460365d4' 
  AND token = '8uykNOaRUCyk/Fi7IRxlpywVaI8eAuDyxJuskaOhCH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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