SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3943ef5d6a570f98d6059975e2d8fd73fd33ff543240caf9cc9d426476089583' 
  AND token = 'svq/4OOYwpkYiOkWbpKMSod5nrf+z3ebfKjE2TPAryQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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