SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8093a7f48d63f924e011b52a863c1213e1c458919eb6fec557b45e974f0beec' 
  AND token = 'bjdX8y7DeZ+2J1SrBCPjCyIZedGg8U6xi6BwD3WtVp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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