SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb6d99745ca9e43423bacb3f955505a1b49f4f2d58aa544af994c6144458bb96' 
  AND token = '4FZSCvA8JjgWIT5MFn6RJiRGnmuvy8le5f0hIZdolb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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