SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c401ffdfe155622b097ce8ed09cb611c33ab1173ef72a5d2ca0816f3f3046176' 
  AND token = 'k5cuLmbxJ/n30DnEeSm+6TB7aK0dUIpaxROS6/wcRIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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