SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'de28d4081160afae16dd00a2e4d9ac4d9e856a206b60abf86d7dedd7c060920c' 
  AND token = 'NzDb/0eimmBu4HhxERCBx+ykvGlXVr8DS+6sn9ebPQM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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