SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b20b2ddea70332ca21ce3807e52b6127184cb643731098e25d879ee7a6f76f8c' 
  AND token = 'SBhj+J31tvk/BtAQNZoM0YXjRL+bUqeC+8VfWineaAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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