SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '54f17d5d389c151c24e3a69ab2b3939cc121fe37abed4a745b1f41c75329a17d' 
  AND token = 'ikW9JuejyYwxxlxtuqbJ089PMLQBgBlkQoPyOQYqmWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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