SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c301d07a1809121bf48d14f33e2e653e2fb4c6d7c67280cc2afa83bc9e558382' 
  AND token = '2lXh4HY0P4PU8p6LzDyWJ4zv9L6Wek3YdtE3kG29UwU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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