SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d250ddf4781fbc461d3813279ee0fd00d00b777f0dc1d0dd74748a72ba55065' 
  AND token = 'hjUJ5CgCjinI6v7RVNw0YTnhGLtkK9Uun6zG0+3T4ks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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