SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82287b05f6e34d3dfc4d42d31f2294895ca53a7314d9bb8b9ac692606b4a4c5c' 
  AND token = 'zlLuFWJDMs4j6bgAxqocBDRqFCS0LkNGdnYGRtbDEgo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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