SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '656f8cd5b9c8f1cd6d638f8243f2e74d0f565b10510a478a6cdf87ccc29883bf' 
  AND token = 'UwlX3knC9sJHXpxsf3reuVM9mEz7By9qDvsPjKtICgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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