SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '329a19de4cf402568eb13ec35e0ef639f66262e5c018c166c27c9fd89d4542d9' 
  AND token = 'ppQ2NugsVUrwADW4TSpwIg8zOlFRXsKHOp3sMiZMMk0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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