SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a9df7d8bd2c264bd8049c2a4a05eadb62fd419774501fc5cbf7d62c86e3481b' 
  AND token = 'KFaMaxkt28Gdv9VAgHREMWtV0W22tbD5IJWdlGXdBY4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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