SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff2eb87ace94b63efd6f8c4728b4f3a6dde0a411b748aef9255d0a41c1316005' 
  AND token = 'HY3oUdML/qr5W4gDzJLC7aiFDObkBPHhBKcgm6ztC4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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