SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63fc71446ef90bec8d3380734ad1be7e2a111b908204829501fd0addb4499bf8' 
  AND token = 'C51I7b4fggt/Llx3i1dF8wENft/xm6jrpgXj0VD/E8A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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