SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '58de38294c0e9284d7c56692148a6e18106c595c91fe4ccae31345eaae379789' 
  AND token = 'NP4nEp8+PiL696fTc+iKDPY1Zhrep3orM8Aax9WVj9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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