SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a9adf24e7dc74a1d061fb39e4a0e635228a53d6bf22783adf7673a259787d2f' 
  AND token = 'zv9Wz3/W/dDVDzaepN34bbvKwZE/ugg8JvTBOKOYm9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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