SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '883f9df2136fc4260cae903f2877552600f4494c1fffa58230a7202e3be1ea02' 
  AND token = 'YgKV3tJ/xUkpqRjjvdC3TAQgpt5JUzvn9rTJeAtQaVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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