SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6f57edd57e5d682dce8213fd0a5f0ae67032d954d120b15aa2d0bae7f0bc0e9' 
  AND token = 'KcgviJIrVraOcJSD3kaM1eUMGykQ6mlmCo9iYfKl3e0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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