SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4380ada05d17aeb080564591474896586571e04c4bd5f3c948f5bb8452df0da3' 
  AND token = 'MEJ1a9ajVTMbLjRuOX1kxdOdR1wkJn8kQoLhqTHcJsk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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