SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71d74492cabe4391d646a1c301d95926af84bf4ce130ef56a67bbe177c9d1cc7' 
  AND token = 'LqPpASABSZo0XCiH0v8qXBY49tiqsTG4y4lIcMBZvYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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