SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd36307054a075e462b78a4c7cee593a414e46607cf84c9d1593ea1c38c2403f1' 
  AND token = 'ebF/fwexgfDokCAozyeIKGEXErYpujc70GfoGq73yDc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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