SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6b535ff28e05d4a8ff52b9c35396528bc0f95b2a61db3e4d290377b549331305' 
  AND token = 'QM7wzUEYUps2eTeoZN6ZOYm59P6aGdAU9XpV4OnxXss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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