SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd2665ff6ea5ad9a908824ec6c2afcf18666fd9aaeb79d51bf957663c5403e41' 
  AND token = '08rvt4oTVuJIw8IB4/4ssZCv3SG0Y1dJ/t2F2Fe4cyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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