SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8285d8012c9809ac511fec26fb2eb33187aa9abccb40b3e66c2e929b2b09f07' 
  AND token = '1DZJ/Nh/kmwK4kTcvPvo5U+ww+Oq0nwGnprtsjYbKKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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