SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0b91e4771ccf6bc33dbc939beab25610f42ab132e9291a0041c6f0d827d462d' 
  AND token = 'qHSkOjmEN1lJetkmcb4jHZMtuwqTpoAO3F45IcQPypI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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