SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8c5808bc10aa719768ad370f3eadf9c257cde8e51f690c724550df73ffb0ecc' 
  AND token = 'KZWK2bFI9XInzz7PkUqB1QKh20xdJNRNHaHtOFMQvTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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