SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ce39e48b9f1ce1a6f269c635102ae51a93f9b797013ee89ee597471e64e52d90' 
  AND token = '3FmjpwN6ppz8tdPFiD97UPQ8rYxwkNTUmWTPISoeeFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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