SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6f1e23233b10520fc896a717e99864c20291a376368cfc808405a55119e891a7' 
  AND token = 'ArrK3ekb4b92aqtfZu3UGwHwMd81hNYLacTXknfmrHQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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