SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '350b192d089a889007528cedce0180863a8c58e93e94e928e9633299019c1c35' 
  AND token = 'LDZ+BJrkV2U2PqyJZyHzoZHJgcZyb5uHKa9VMENa12s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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