SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd859ad73f2124cbcb9377b941d66d81601539eeea651274cf367e05aca72ff1c' 
  AND token = 'KQ3o+gkKRNxrQNNwO9B/mlWfWzYVe+8+K992ymJZgXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}