SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '195e7d28fdb81d9b80f6f45bda707541c8b66740ae934d655f28984627117241' 
  AND token = 'P27roIqYpTUDxnrLvyzjUQ7oBA2TEL9sFRBtpRp95y8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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