SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '56ccf348c6408b98d5c69a70b5f6304d9f6de392627fd0ac1cb1bd540ea49164' 
  AND token = '7sX9TK/0p80Er0Yd0Ri3LMMq4po30CBI29VvvzpzwL0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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