SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a03f5344fbdff9579e102e645f0e28fea9b5b44b1a56c7e15695245390eb84db' 
  AND token = 'HmxmKfPftLEpCeecdgI9MbneQWS+J5E7SJ92i7GRPC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}