SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b2c95ec45c3b404b31a461d39825bb724414909edb749aff787310a630182f5' 
  AND token = 'C1OsL/db0K829VqgtkxOED+4xmAGyWXPojZWX6+U6HQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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