SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cb611c4d5f6d86649787f737f0052176a5151f0637cc271efbc1d919294fd9c' 
  AND token = '/x3dMqHvOq9YHxzWuATuL5VJzbCxfIgCQWfYStxKfOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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