SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0311ae3d1a228773cd8f350029590beedbae957a89151915c5bfdbed920039b6' 
  AND token = 'DLyESpgkzJvY07yvJZh5/p0lMt2/qR9KI8FNcM5CdQ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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