SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '101ab9c6d84d35d19f09a7fa69eef00107143ac107a9b5e7271346ad0a727faf' 
  AND token = 'AqKUl40t6BKEYJcWB/QAnHsD9f+WB9WwBvkQoev8LsI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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