SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa3e6ca4ce0209f305582a8cb46562e977f78bf664668d680381c8504744cd10' 
  AND token = 'RZ0HcBQUjtReNEf6mc+DZ7KCkm700VegCNn9B5wy7Lk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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