SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b48489d2109c6411fdb9a70fc7ae503193e279c4eaab512710983fec307c4cfc' 
  AND token = 'WRbZhBiIX1xmSAGieoDl3fI6vK2qDp1z+7M4XMisqw0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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