SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '641e6dd9bc9021550b6c7489e0701d2e33c9efceb92dd16fb551bceee3c64717' 
  AND token = 'WZbDTsW1VzbDFpNrp1wE79D3S15pqtQGmyWA80Genc4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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