SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7f09dfcb6e07721a442f4e7aebc8e8f58d9f1e4dba404bdfd256942e0e5aa3e' 
  AND token = '3/7azUFnMKZCjknxGa56nUWB87qxcP3iyXiN4E5va3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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