SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dccc344eb967278375ef402cb96c9a0d4520b4d7b359a5b51635732578ed5f66' 
  AND token = 'wF5Glldr5oHywf2+K4FF/AABZvzljj3UiF11RXsnLDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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