SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bc3816c90142bcd16900a399fce52a72c38b42650800bd86bcbce5c9aefa830' 
  AND token = 'lGOjplQs59bYNAhQykdjctNSdl3wL0oMU6LnvvOKjhc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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