SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3db304c87c9e95075bc05003ae2691e35d7344a2072381971d9d5d3fedb10347' 
  AND token = '/GolU7l3u66MaSzoZnHI9SdfPoHaj0IFHJVWBHefWkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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