SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e73cffb46b1dfd966f11947bceb58c1752532b8339f1668cd2b8a56820727905' 
  AND token = 'boOw8KQMKaAjraga9a24TQHOwXTt/TEDzfTrrmOn0JU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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