SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e4549971d4748b364a50c622afc64b756ec8daf35f39a2f5c077c7fc1f8712d' 
  AND token = 'eAiKkphw1bowadoDKlVBgJPB+K5+vqQQg04GdyE0QEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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