SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5729037885d13adf5bd0cdc5fc09e7b7d3495f2030d517a81afa022f2a3f8fe2' 
  AND token = '6oNgtjAuUsG+56HIXgufsy+T9P2OAqybyoL1grIcM3I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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