SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd47d9cb50fe5dff8fd4235d3d8286caa73316f883fced6e43f8f052602737c90' 
  AND token = 'JfowCgMP0hJIjfCO9wmW0gmbHxOIxCBVDzskgDXTph8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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