SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa4f4f8ac98cfef046f925cfe6ffc1639e058f994138f8951ee33042969f8b50' 
  AND token = 'yqA9S5WBB9pQnFlbhlpSVldTsHjbPTE2xgf2UHefLcU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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