SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aaf5e40c60d8413008217ec0f8ead2f3312b0dcda02b53a2329144f896e6c41f' 
  AND token = 'UbcP8CPAxlpUs8dQufkiJqkIMa5E7ky+GCgcJp2NqZA=' 
  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"
    }
  }
}