SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37b6bd36b2e99458bb8e4e09789b03e9112f7a7c5b5d1ac25726eff88a1ea0fe' 
  AND token = 'GYiZqyj/gFT5mOb9Y9sIPMnA1phQSYqXAcPJDD5cwUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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