SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adaacdc8f947a095f0d20c44e2e8bc2467370b69742b43564f9791051947bfc3' 
  AND token = 's93IUDxcGPs4H5VaLXN5MwV+Bz4PTwRTque+qYgZyrQ=' 
  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"
    }
  }
}