SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38c293c281ec616cc07c8616804e39f5b1b0748f718beb4eaa1be091a10fbea2' 
  AND token = 'UftiLCem65WglFpDBJkhNYYAZNP35YFE/f3hGaD7Olk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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