SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c375058cc71e842a7fb3116a637c4fc75a93a2bf5e5536f36162e818de8d8376' 
  AND token = '79DmEp4nfNhcJ/ZfcsB57d5tMQ8b5cttcAL51t/xT+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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