SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a443c22330115fa29f930ea8bac2b2d054a6db347f1f9a3e553ab8bda66b3850' 
  AND token = 'sXKlqrbphk8ebeGg5LyrwBrS8BOnWRU2l2N+3Tn5y1M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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