SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b18e342de27bb47903f026c942b2b0662f62368cecf594b1ee86d475a21bd10' 
  AND token = 'vVJnvuCU8FrnH0BLlJcb/UZtloQUtfIHKXLXzBLQ9XA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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