SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd97c9c73bb3215fdb17802f5023dc1cc4df69447e8dc96735b8212ec3bb68940' 
  AND token = 'BwpyzXHGiF4euOiHXXRplVcpGmDbvCFJpqxiY3J1noY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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