SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7608bc823ed32ddd9dc9fc560e6d3d450602a1ad970798f7a0431953a27311ba' 
  AND token = 'JTzAkq18fid8fgUK6AjA78ouVMsBzvX22ynfQXNMin0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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