SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ed5f966b9462838006f698158bfe7d2597c9c13294658f2ed7f7abbb67ea270' 
  AND token = 'qUkQSURegL53GGstanyijAzoPjZlZH7h0YS1+zMYjVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00067

JSON explain

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