SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fdc84278012759a8cac5211e9e18f151c3c0f7003b676a864cdd6d3b7017485' 
  AND token = 'u5/pKy5IvWKCxUKXGoqYS8W8JqXSCWluO4hDi5wh/cI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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