SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b5592dbf3cc0fbc1af4070ad693650ff1a216580212a7efba78f7b7def71feb' 
  AND token = 'Xhp225yEuPMEyyFmrRjRsxf04C5Hc3ugnSluVKdrRuE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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