SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a835a55d6d9fe24e5aed6e19125d1abff0c79d90e29e53fb7b38188e13854508' 
  AND token = 'eAo7rZDUZUrzmTU35zdv2j08TWbQ4ZO53nV6vhgW7xA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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