SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc1c89213b3b281ff95567f99eca089add2f8ba0c62e30a425317f57ce6867f3' 
  AND token = 'WUwoXvVUcEfHjTTuRN5zxE1zrOyIJhBLcbvNIiBm+3E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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