SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c629dccaddb7746d10ccaebf04cdc41684c26a04b36a765a2084dc66d7b3377a' 
  AND token = 'QU8kzq6TDJ8UWuBWivWSCc7rZlZ2hoXM6HmE/hvoyt0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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