SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db29ec316b34f589ffa5d9cf349725b2788f84e9c98ecf6c23725f769d083ae0' 
  AND token = 'qNG4X7FUwXIYtGewiwmliggG5yl+Kz3BPo1lq2GziMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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