SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '86c8fcc672690bf5c20bf9eb742abfa8cd74a292bbb7866bfba0f96c5c4fdf34' 
  AND token = 'FzAZj6bB/dMHoh66egdUPy1yTN8fEyMWXSRqfkr9XXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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