SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '939414a93f1b51942a25f8774a6d387158c5749e011c0a658c9741e9ceda3f05' 
  AND token = 'fH2KQk5WV+Vgg6w7qBj0lBbPKJPRY2HTfGc/BofX0sI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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