SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfce4308f9f20342b36191935b16a3098a4a9dc955ed85f2a75d46b89937c4a6' 
  AND token = 'IYCQRmGE+2S07gJQcRmCB3kaq/Cply8WwpHCslJ9QdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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