SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adab7c646540bbd1d5be3c7ab0e8716a407f2dd7b8387cf2cf09caf32200249d' 
  AND token = 'vTx5gD6/++DGnhoJwJTkcXDg+EpjU3vdX1ze0v9oB1s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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