SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75a47ca88ec8ea59067b8541385462303b85076d3b796470a4f478786fce78a1' 
  AND token = 'OvEn+KMMtQWtA/IzW5xNOz4qgerVAXKGjfL9ZJhQRbY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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