SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ccccf6554eb7a29836b29aae89e465ea7310e8f1105a5f49735009fd35b4801' 
  AND token = 'lbqoTD77VLg9BJ6+9foAqERJEnJJRM84weQOAiBvGdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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