SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '324011040ee4cfd8ede4972cd9b075df142bb6feaded2fe110e150363046b3a2' 
  AND token = '3AQrDynjvfPiFQV1HZqcWBqHz+KtK3mpt0XA8vWY0SM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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