SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d9fd43d6e7202ca0019b13dbc7c391db80a902bc013bed59734128b7d09a262' 
  AND token = 'lltRJNzyMaMcESajP8unNT/6i++9iEs/CCjoKdveCMI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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