SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b029746dc51de43a8cea488d6aac80a02bf8b83b126568c57508941ac8f5ff0' 
  AND token = 'MtZpihPzjZD9anNUgO4P3oIjJKmY2Sx7A2N4teF86Dk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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