SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '51c82e6ab9fe815dca5518542481dd2e48d19f28e72cbee2cb1163be9a708706' 
  AND token = 'C1sdPl04h9ETXepKaIJkj2ad+9D4lfCqpTwrD2BaDT0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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