SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '154cf09fb433840e38b1474df74662362b85d144698df0a6f627190ea1a9c9ad' 
  AND token = 'X4IWHznBDpQB6qZxNjsIUgOZyoMmlzzOd9FzyONV+xQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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