SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a394cb25d5675ac0bc7643879c39425b9f7da775e9feaeb3aa1f161e9a4ec60b' 
  AND token = 'onW7F8ABbs32Sj4TBNo4yBk0sc8kn2bpWAVyqnxrbZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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