SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3f3a0ff35d8087f676e3bdc71240567e9eb51124fb19a010c30f38cd7a813aae' 
  AND token = 'fXct5I7mDRiLb14/5pxK2l+Kr/IKZxRRU0TUgdF1rjg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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