SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '742b85e21fa6e8010131bb55f24d0b1947cf5c60ddd647f0137533767800f2fd' 
  AND token = '6llxpaWU3854yzCZJNUh/viDNqEYAUKuf1x22naJ8bU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}