SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '517b78412a3333c23744c22a35bf30af37402d6fc38ab6528d9428088e9a268a' 
  AND token = 'rl0vy1QktJkmZt9RG4HZNo4FnhYN5Grl8iZbgWb9IKo=' 
  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"
    }
  }
}