SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc93020f6e49dd4f86d26ac8cd9ff4293ab1b51cb44749d74301effc47feb6c4' 
  AND token = 'SedwKFgptwgVfmGtSLv7hrgfdxhAwinQ+riysVbwW2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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