SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7f215c0741557097a30d1788fd1846e09ac520dcf868c344fd176ff519bc7cc3' 
  AND token = '8R+p/gH4NFZn61c19yCO+HgguJQ0HGsOPu9vOQwv2K4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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