SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ac3fc8c451273e5697a96c670e07d0ec3108a15c204ec1f59b095999b494799' 
  AND token = 'XhBGOkd61vsOHzuNxkpySPL9ZJnbNQzEnustZT/kBXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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