SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6751607c6ad48937878c85a50d44b629fb7f8789af6e6631c44c6d643a1e3206' 
  AND token = 'Pby0tzU5mtUIIm+T5GY1DqL0Yt0wSsojzyEUNvQYGUE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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