SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3a49dc90580b4c1171f095db2fa88b624b18e07553c789225d49ce47e88de3d' 
  AND token = 'mUFGMxqIgnfrqh3VPQRyOZImLqRnRHziUXyHCcYiQy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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