SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10d2973ac5160f220e1c653a86deb9c71d90c572441a5e36471caf9c278619c2' 
  AND token = '4zWcTM8aNRK0RVE9RgSjCBtVt2T6abtIr7Plg+Kpck8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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