SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3cb28394530cb36f318c2ce827ec429599d7566fa949a31afa3a1b3a3c9618f' 
  AND token = 'WZQsQzt/Xq5mJCV8hax7kwbASAfvVUk0hYh2ctExo+g=' 
  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"
    }
  }
}