SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28a79d9b60220acf6c622525fc8dfc3ee426f2eb81034fbaba1b560f950021ed' 
  AND token = 'QSbn7+1p1KUkAJFahyrmcgCrShCwWn/SlduSImicFsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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