SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4a68259d9332020a658604ab0935b82b6a0c59d87f20bdf5d7f64a871f20721c' 
  AND token = 'HpEiUUmYksf0+KuqEV9tVUnbq0svAKxu2JdooB0joro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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