SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c68ee9e182bf267731f4fe0b20d0d27d119d9e1e08e8275c0f92a05f6f6408e4' 
  AND token = 'DyhYJFJji6lvNPbJ43wJ99ei/GmmyiJ5yMruFi5cJpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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