SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4271829e4433552bd083f715f073931921fc4689057b2d1dfd882eab5bf610ff' 
  AND token = 'TsaFVtwz+7fZkywb5Rl1ThO3vghlTf0WuqxXINq4vt8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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