SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bb8d9ab51c6db69dadec9590aeb7ba2b4fe356a3622e61559a490b0da7b6918' 
  AND token = 'FxXX9DGEMrYqXeOLTpo1r3YGjkoTvgXH618CZn3bkl0=' 
  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"
    }
  }
}