SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4102dabf92d5854aeeb9d26475f30df97bca24405d7464a552ae3ab19cf946e' 
  AND token = 'BOb3sQGzsVORlPCrmGOS7keyzlcoM7Vcg2Skbpp7Wi4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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