SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91faa01c23e76a2b03df1e060b494f76dff5417510213c951a08d6457a705564' 
  AND token = 'ho1vAnNxwPDXKs7gE2PUs9zVqBd9F8+689Unb3cVBpQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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