SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59f6af66bf122c908e8b6e1cadb0aac71f7ae6eed9e2af9b0ce9dd8cceca802e' 
  AND token = 'RYxMQcScr5QLanDbeTl/o+Dfu1JpW/IGDMOQQ4zZOPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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