SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4a6417440102ace6ae0687865ad4ba692a0c18cd70990e11b884366ab8f88f4' 
  AND token = 'ul+6AU9kxMv2UDut129kLXxqU6X5s8ZwvBCeEAuKSko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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