SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc4d88ff7fc5d9bf81bebf143ad778f80b8b1ebd6927d2653bb12b09aa14466c' 
  AND token = '6soa3uiYUSCOWaTwV0zZaScwnhNrjFvqh7Dq6uQyKLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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