SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39b9afc18dbd1d8640561be0829d346acfb331cd167ad953ba4cb7938089179a' 
  AND token = 'HKj4ZxdxpDyZbw+xVDfLhDt4vPK4g+GXjoUtkxnimW0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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