SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b61aade926d0051f4d7e72faf38fde8bf6b37bc6e17c08b7b09f85ecbc92657' 
  AND token = '/IZFviwXilE2HbLmPYhO+G6eiLL1/yrmjwOJ8j7YDmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}