SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '104b62e388d2a06b8f41270bf2383405c7a9146b8673204e864a91a6af2ce50a' 
  AND token = 'rl3nuQlGirZhCVIMFWXlGtHXzgDotDfNuQ+68fggzxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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