SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a34a663ea16705ee873c9e31cf4d75e22a6b08ad885964842278ca943816a53d' 
  AND token = 'LuJNJP6/eDyQMcvaPTdx7ZG8JQrYBcvWKbqUf9wjh/c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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