SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b84724d067e394370d11a43975288ede2161c3bfd2d0536e90ff57dd22dad49e' 
  AND token = 'G6HCFqXK5QzM2Y+/4zcp8lQBIIJshE15MgNCYqxAh4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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