SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b8d687ea7db4c90b4a4f44da05eb608396ab169ee51232824101c99d913b257e' 
  AND token = 'Eytk/CZ1IFjlSJtibg07g8XKlDIH9S6R00chjxjVYnw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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