SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'edfbe2434fa6c5fe943e909a21ac30255947348fe708adfce2d17370c1f17cd1' 
  AND token = 'XjrccjD9k4GajC6GTIWrJeMW+7/q9uRZkBLxvG6NRRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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