SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a54bdf8b3a84fb5fa410ef9015890ac26c22c81b18be35138bdb3771f19fcc8' 
  AND token = 'OQyVjOw+wv4Rp9OVhzlzinrXyse68kEzn380HAWbSn4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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