SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f31e549d5e7385ee8f683e45a914536204396d0bfdf7667e2db7774f6b404693' 
  AND token = 'n+UbOZilrRYTrIUa05VHFNgjE0wyDDGPbDqk1C0eSkc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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