SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '598466c919fe0dcbb2964f15fd3a8cb2d129a0a6ecc3901ebab68efe6b743838' 
  AND token = '+W3LGplh98vE2RaI6gs9GOleSaBwmXV2msB5J4/xW3g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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