SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30736c3d762fe77ec3e5302cd5ddfc7a1d474e6799f432d92757142f0e6eb844' 
  AND token = 'BgUKNUZrWjcEkpzm29QAESAxw5akOv4T1di4Cq6vGnU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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