SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3449d3d6c69cdca7e923493bd6c50dcb60036e92220ccce6331fc56d42ba898' 
  AND token = 'UQzpOhXfSDtsXtQk1ZIiev2roioo0KpONnjMLDrooSs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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