SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c8c476523dd3dbaea8ae00b9a3cd4e260f743547a1317d7e5e067c090f8c29b' 
  AND token = '42uiIfV4e6dsqJGFelwnKzjVt3T2L41MuKmctHZGBVI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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