SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf164c6e139ed230ed2b447a5b6dbed6da75b376fc5c6df2533b71658d64a74b' 
  AND token = 'SqD/OaOHblrnj51Lh5AVSASbsrEL1mvLy8VlvT3qVSE=' 
  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"
    }
  }
}