SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '017e8d0ebebf7d6af6aff7374d51ec9aa5e07fbbc00a6ec7af8226423717829d' 
  AND token = '0uODqeyuaYNrLIQAfccHXlvRJFoOv4x99yy6bnGljTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}