SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '086998e4a545cf5b1f93be4c3a97ca876418c537d5834efb5675b4da557babdb' 
  AND token = 'hCeVGRYErUa8i2KPKYDq4DhYNS+kk9C3WOX2FLFs5Wg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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