SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8168a81103a4513eda06b936374c928b814ea828d3cb347a61fef328a3f52c6' 
  AND token = '1QXqFII6DFsiDkxHed7g7ohfH/Ud95q6y1xQR3q/YgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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