SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '10730efb7ceebb3e10a1fbd0b701fe0123ad2b2e5f52ccdbea4dc99c86c408c6' 
  AND token = '4ZdCTuszJG9RaTIokKstT6tEdPvsMQxPIj/WurFnp3U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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