SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3c966fbdb15a8d7503473f025a02c95129e9862f95dbba5072d0947146c03b4' 
  AND token = 'Zxf+ULSFPF9YzfBoD1zJ3u+Smtehm7NeqX2/RNcs+5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}