SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '676ebc40363aabd98e579c0894571aea8001b7c02e9668bb68e1e85ce143fdec' 
  AND token = 'o/Dv9tHmIyNCMnsLLhO6iYJ08JlH2wxkFgvjC+vUIvw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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