SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '87f21f4b723212e8ea669a5f470a8248012f505ab25e5feec868cab01e731f49' 
  AND token = '6igJbmF5WowUdxuaMKwlWVgsdtV2MmaALMHX8uLcQiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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