SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52f7579e8c3464baf642150858ffe51466dd739853e53d2dd98ec7f814fb0247' 
  AND token = '72qfRqDsAJcBYGUX3ELEzVJ0K6SNEuED9t8cnVQhIJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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