SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f83827e8aa19d756efcaf5e7c4f560a0640d9dc29706e6aef49d6bce633b2090' 
  AND token = 'fSSUcN2Wd3fEs/BmgmUOMvk2VEdpnZjuxHkxp5wSR+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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