SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a63923b723be18ee05bf7de8acb6237d8b6038e32ee76f4f714156245a5440a4' 
  AND token = 'G7gpo/a0DkwWihUtW6my9xupqOxNrQPxCyALbz+sUBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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