SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b91094204fe7733c5fb274d32626cbf190ab7b6fe92879b686f8b999e0aa9fa1' 
  AND token = 'h2v/7V/DEdxPT/vyklbe3Kv25jGZJfF++E6LGdAAeQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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