SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81479e2655c63c67888979aaea4616ce01a4aa9876b1a80ae72140362ec06929' 
  AND token = 'kc+W1B9AEICWOZhIBZGCWvZzDTFxOzZwb72+F0PUWRg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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