SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb1cdd6ba12d37ec7db4e0971b9b7b4d60748cc07ccd179f475f0fc1d9596bad' 
  AND token = 'fbvDeXZlUAIEj/XydjEQYxDaES+fcAO7mzHfs4awdUQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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