SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0863d9f2f8dbfd625ca57d5be0ba07a7efc8dbf9f8517cbd96a57f18b1e1b8e2' 
  AND token = 'RDBhmlI1VviUMbsbSoSDQTa2SB1MPQxUScmAUFY0sH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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