SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98cf4cc430876e8cdd081fe52c48ecbfe683e147fff6516bd503ce454f040d71' 
  AND token = 'vaHu4gx5I+ttY4ec+NAEsibKaJYYTEv8wnQhJIvti6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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