SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca0cbf19886c750d316bf16b64f2f3e8ef12bb691aa2758f3567853a5ec1a551' 
  AND token = 'AuWG5PViwbsuBy3dvdlJhDENRtvyxhv+b8EiuzGyAuI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}