SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3343ebe2b3f23c4bae97f425184f8acb0af14ba94bd757bf5b84685a151a7fae' 
  AND token = '4QCYzIQy06LR0g9k0lXZO6kHUXIuPb+j/cihB16qmyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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