SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efc275ad575d50c7629b4a86e04a4c74f6b23896c93afcbd62d798cd0105afd8' 
  AND token = 'S6KQJ0jaEBZR3qHA3cJhHhwuu2U4sYplH08iYy6zsZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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