SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ea80496fc7d399b38279830785992e1cc2ff73a4757ceee1646b869b3a8ee6f' 
  AND token = 'YtbmBXIYC83N7SuthFkgRX7LMdP/VU1x0su9uKlUqOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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