SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a656b4a18d9d43c2fef4813da911019ca2e77de090a81b0b151b477f43aff9d' 
  AND token = 'OtVfxTcUWk0T0VM5xBOheOBuS9ZfrHQJjMIDipcUKsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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