SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd0fef182bed8dc06aaaa4ff4ed7fc55ee8023912847486691e180b18e3c91902' 
  AND token = 'YWZqGPpUCCseCxNsWFaLjwrxlj0QSx5qvIMqXJfSXu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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