SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd06c3b4eacf33988d83cf4cfb19c73efc318830642baab147678ba8a0048ee70' 
  AND token = '3O6zSIxfTOWZ9ir3h4pU4OGQw2PhFqBGcSeKcOHWjcE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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