SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90ad129b46e854ded09d7749702c1bec56ced5e9e176b8893d74f0c154dc7f6b' 
  AND token = 'KvsQDfVwh5Gki/MksVkNekg9jLjoSLM+nHu3tdrIYMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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