SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1963f6e2c3ec83f57fae12dd044bc8d1b3be1d9b15974b07e18cd9cc8cdceebc' 
  AND token = '3oGj4BOM5MLPvP6YFhCn9JmKwVJ3wX6lPziSguJSUTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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