SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a741fee6963706c22759e4f7fd2c51bdbd4d66c5a85c73b23e62936d349a3d9d' 
  AND token = 'c1tnh2DxhFrXrtH4yYirBL70x5TNl/DFhCM6Vf74GxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00069

JSON explain

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