SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd42f9ff973288ace50a07e1b8766546765f03f601c6f5d2fc6f7a4d337c388c2' 
  AND token = '1KaNfMq0PFGJzySzZ4buLPJzUl9Bqj6HuLUUKCZgsoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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