SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39476d4fc5a4a4be02d11a0569251e840c7a4d8ba9bb67ed2507ffae58197f54' 
  AND token = '24ufzSuxnG/mfndUDo/83/vl/VSwsJbYi3KG35ZXvWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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