SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c08d5cdda6e99962e375d812b0f820f575451341740c24e330455514a25496bf' 
  AND token = 'LwpS713jkOLoiDNJzg6TVbqGrJMqUxx2300/7dhYczY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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